Cyanuric Acid

[Sue225]

I cannot keep chlorine in my pool. I added ProTeam Mustard and Black Magic 12 OZ, a double dose last Friday. Now I cannot keep a chlorine level, added about 20 pounds of chlorine since Friday.
FC 1.2
TC .7
Combines chlorine -0.5
PH 6.9
Hardness 20
Alk 110
Cyan Acid 100

Pool Store said to add 15 oz of PH up, 30 pounds of calcium up and 1 1/4 bag of super chlorine followed by microflock.
What do you think. I am beyond frustrated. HELP

Oh yea, I forgot, we have something on the bottom of our pool-brown puddles which appear to vacuum up easily but then reappear the next day!

[Watermom]

First off, welcome to the forum!

Secondly, stay out of the pool store unless you have money you don't want. Then, they'll be the place to help you out with that problem!

Your CYA is extremely high at 100. As a result, unless you run extremely high cl levels, your pool is gonna get algae. With low cl levels like you have, you most certainly must have an algae bloom brewing even if you don't have a green pool. That is one reason why you can't keep chlorine in the pool -- it is being used up fighting something in your water.

Give us some more info. What type of pool and what is the volume? What type of filter? Also, tell us exactly (meaning ingredients, not product names) what all you have put in the pool and when. If you haven't done so yet. don't add any of that stuff until we get some more info from you.

BTW -- FC + CC = TC so there is a problem with your chlorine numbers. Did the pool store test or do you have a kit and if so, what type?

[CarlD]

What do I think you should do? Well, first that pool store isn't going to help you! You have been "Pool-Stored!" (and we all have been).

BTW, how many gallons is your pool and is it vinyl or concrete?

What we know is your CYA is SO high that unless you raise your chlorine levels very high you'll get algae. You CAN maintain a pool that way, but for newbies, it's MUCH easier to simply drain off half your water and refill---that will lower CYA to 50, which is more manageable.

Next: Do NOT use pucks or powdered chlorine unless it says "Cal-Hypo" or "Calcium Hypochlorite" (something like that--Calcium Chlorine is the key). The pucks are "Tri-Chlor" and the powder is "Di-Chlor". Both RAISE CYA (and yours is too high) and LOWER pH--and yours is too low. Cal-Hypo is OK because your calcium level is extremely low. If your pool is vinyl, that's not a problem. But if it's concrete or plaster you will need more calcium and the Cal-Hypo is ideal for adding it.


pH Up! is just a very expensive version of Arm&Hammer Washing Soda (in the yellow box in the detergent section). Same chemical. But it's not a good choice as it raises TA and yours is, at 120, high enough.

Instead, you should use 20 Mule Team Borax (may be on the shelf next to the Washing Soda!) and add THAT to raise your ph--your first goal.

All you need right now is Borax and lots of plain, unscented bleach and Cal-Hypo powder (if you have a concrete pool).

OK: to recap:

1) STOP with all the pool store stuff. They will empty your wallet and fill your ear with gibberish, but NOT fix your pool. Most of that stuff is garbage or expensive. You CAN list for us what you have and we can tell you what you can use--list ingredients as the names they stick on are less than useful.

2) get us your pool's size and liner type.

3) Dump half your water and refill. Sorry, but you gotta do this.

4) Increase your pH using ONLY 20 Mule Team Borax. Add 1/2 box to the skimmer, wait an hour, test pH, then add more.

5) When pH is good, you can start adding chlorine. I'd start by raising FC to 15ppm using bleach. 1 gallon of 6% bleach adds 6ppm to 10,000 gallons of water. Adjust accordingly to get your pool to 15ppm. That's ASSUMING you've drained and refilled and your CYA is now 50ppm. If it's higher, raise your FC to 20ppm.

6) Check pH and FC 3x a day and adjust as needed--beware: At higher FC levels your pH will look high...that's OK for now.

7) If you have a concrete pool, start adjusting your chlorine with the cal-hypo.

And report back test numbers. When your pool can hold the shock level and is clear, you can let chlorine drop down to maintenance levels: between 3 and 6ppm (again, if CYA is 50 or less, 5-10 if it's above 50).

Good luck!

[CarlD]

Watermom finished her response first!

I got side-tracked. But our advice is the same.

[Sue225]

I have a 24 ft round pool 4 feet deep grading to about 5 in middle, vinyl liner. I am told that i have 15000 gallons of water. The test I listed was done by pool store. I have about 5 gallons of liquid chlorine on hand. I added 1 gallon of liquid chlorine last night. Reading is about 3. This AM my husband dumped 10 pounds of calcium up in the pool. We will not use the other 40 pounds they sold us. We will begin to dump pool this evening. Should we empty 1/2? When can grandkids swim?? How long would I keep the chlorine at 15?

[Watermom]

If the test was done by a pool store, that further validates what we are saying --- they don't know what they are doing if they give you cl readings like that.

You do NOT need calcium in a vinyl pool.

If you empty half, that will put your cya at a much more reasonable level that will be easier to manage. If you're gonna dump, no point in wasting a bunch of bleach. I'd wait to shock the pool up to 15 until refilled. For now, I'd just throw in a couple of gallons of 6% bleach. That should take you to around 8 ppm of cl which should kind of hold things until you get refilled. (If you don't do anything, it may turn green in the meantime and you don't want to have to fool with that problem, too.)

Get yourself a good test kit like the Taylor K-2006. A good price for it can be found here.

http://www.amatoind.com/taylor-k2006-test-p-555.html

That way, you can test your own water and not rely on that pool store. They're not doing too good of a job ..........

Repost with current numbers when you get refilled and we'll go from there.

EDIT --- Since your pH is below 7.0, go ahead and add a little Borax to take it over 7.0. Maybe try 2 cups for now added slowly to the skimmer while the pump is running. As long as you get it over 7.0 your ok. We can tweak it later.

[CarlD]

As for "when", we won't know until we get further down the process.

Calcium's SOLE function is to prevent the calcium in the walls of concrete/plaster pools from leeching out. Pool stores regularly tell vinyl pool owners they "need" it and sell it to them.

[Sue225]

We will start to dump pool this PM. Do you know of a good technique to do this? We do have a main drain. Where do you dump this water to? Yard-street?

[Watermom]

Heck, most of the time, they'll sell you one of everything on the shelf if you seem willing to buy it. Do you need it? Doesn't matter a lot of the time. They'll still be happy to have you walk out with it.

(Not all pool stores are like this, but too many of them are.)

[CarlD]

Use a garden hose as a syphon. As long as the outlet is below the inlet water will flow.

[Sue225]

Well we dumped 1/2 of pool water and are in the process of refilling. One question, the liner looks like it is rippling. Is this normal? Also. there is 0 chlorine in the pool. Should I add some bleach? Will it be OK through the evening and night. Looks like we have about 8 hours left to complete filling.

[polyvue]

Well we dumped 1/2 of pool water and are in the process of refilling. One question, the liner looks like it is rippling. Is this normal? Also. there is 0 chlorine in the pool. Should I add some bleach? Will it be OK through the evening and night. Looks like we have about 8 hours left to complete filling.
As it is refilling, try to straighten out any wrinkles. I don't have a liner pool but I've read that some people have used a clean toilet plunger to remove them.

As soon as the pool is filled, re-test the CYA level and add sufficient liquid chlorine or 6% bleach to increase Free Chlorine to about 7% of CYA. E.g. If the test result indicates CYA= 50 PPM, add enough bleach to your 15K pool so that Free Chlorine is about 3.5 PPM. Or just go by this chart (http://www.poolforum.com/pf2/showthread.php?t=365):

The Pool Calculator (http://www.poolcalculator.com/) is handy for estimating chemical additions.

[Watermom]

I asked Carl to talk to you about your liner rippling . He'll be better able to help you with that than I will. As far as FC of 0, you need to get some bleach (maybe 3 quarts) in there so you don't end up with a green pool. Just pour it in front of the hose so it will quickly disperse throughout the water. Then, once it is totally filled, run a complete set of numbers again and post them. May need to add more cl in the morning if you are below about 5 -- assuming that your cya will be around 50. If it is different than that, refer to the "Best Guess CYA Chart" to determine how much chlorine you'll need.

[CarlD]

You can sometimes move the liner with a toilet plunger, but obviously get a new one :eek: If there's too much water in the pool it may not work.

[Sue225]

Since I have just dumped 1/2 the water in our pool and refilled I will not be buying a new liner this year! All of the puckering kind of smoothed out and I have a few wrinkles which I can live with. New liner is on the list for next season. I will be getting the readings on the pool since the refilll in about 1 hour. Will post them asap.
I have ordered the testing kit you recommended. Will be glad when it arrives, probably Monday.
Thank you for helping me!!

[Watermom]

I think Carl meant a new plunger, not a new liner! ;)

Happy the liner is smoothing out for you. Post your numbers when you get them. Good that you ordered a kit. You'll be glad you did. BTW -- you're welcome! We're glad to be able to help!

[Sue225]

ROFL Crazy me! I think he did mean a new plunger!
After refilling 1/2 maybe 3 inches) less of the pool, here are the reading:
TC 1.9
FC 1.9
Ph 7.0
Alk 60
CYA 110
Borate 80

According to the computer my last CYA reading before the ddump was 144. I am still terribly high. I am going to work around that with your help. Tell me what to do next
I am so thankful for you.

After 2 weeks of this pool not holding chlorine they just today said, "don't use granulated chlorine!" I have not all week! "Just go home and enjoy your pool if it is clear!" they said. When they finally called in the chemical guy he told me the CYA will evaporate with time!

[Sue225]

BTW I have a 9# alkalinity up in the garage should I use it?

[Watermom]

Wow! If your cya after dumping half of the water is 110, then it must have been 200 before! :eek: CYA of 110 is still high, but if you are extremely diligent about keeping cl levels in range, you can deal with it. (I know you don't want to do a partial drain again. But, if you don't do it again now, I'd suggest doing it next spring.)

You will need to keep your cl level between 8-15 ALL the time and your shock level is going to be 25. Since your cl level is so low right now, I'd suggest going ahead and shocking the pool now. In a pool this size, each quart of 6% bleach will raise the cl by 1ppm. If you can go overnight without losing more than 1ppm of cl, then you can let the cl level drift down but do NOT let it drop below 8. EVER! Or you risk an algae bloom. If you do lose more than 1ppm of cl overnight tonight (from sundown to sunup), then you'll need to shock it again and keep it at that high cl level by testing a couple or three times a day and each time adding enough bleach to get back to 25. Continue this until it holds overnight.

Uhhhh........ CYA does not evaporate, BTW.

Yes, you can use a little alk increaser --- it is just really expensive baking soda. Only a little at a time so you don't overshoot. 80-120 would be a good range. Also, the pH is on the brink of being too low. Add some Borax and try to raise it to around 74.-7.6. Start with about a third of a box of Borax. Again, gradual is better than one big dose that overshoots target.

Glad to be able to help. Repost with any questions and keep us posted how things are going!

[Sue225]

Is 1/3 box Borax the 4 pound box? How do I measure chlorine to 15 or 25 when i only have the strips anad my test kit has not arrived yet? I just put 1 gal of 12% bleach in pool. Looks a lot darker then the 10 measure. I have Aquachek strips. Thanks so much for all your help

[Watermom]

Borax is usually sold in 4 lb. 12 oz. boxes.

How can you use strips to test that high? Simple. You CAN'T. Can you look and see if your Walmart has a 5-way test kit that uses drops? It will suffice until your test kit arrives. Or, let a pool store test for you but just don't let them talk you into buying a bunch of stuff.

One gallon of 12% in a 15K pool will only take the cl up to about 8. I'd go ahead and add more chlorine. You may not have anything trying to grow in there but since your cl level dropped so low and your cya level is so high, I think you better shock it on up to 25 just to make sure you don't get an algae bloom starting. Go ahead and add more this evening. Then, test early in the morning and if you haven't lost more than 1 ppm overnight, you can let it drift down to 8-15.

If you can find that kit tonight, repost and we'll give you info about a dilution method to try. (Or you can search for "shot glass method" and find it yourself.)

[Sue225]

my kids and grandkids will be here this weekend. Forecast is for 90 degrees.
they will want to swim. I have the chlorine at about 10-12. Could I keep it there until Sunday and shock at that time? Is it safe for kids to swim in water with that high of a chlorine reading? It scares me to allow little kids to swim in that amount of chlorine but
i suppose public pools keep their reading high also. Any thoughts? You guys r the best!
American Sales had liquid chlorine 4 gal for 9.97. Cheaper than Walmart bleach considering American Sales shock is 12%. Aldi has 6% bleach 1.07 for 3 qts. Yes, I went to Walmart before I read your post and did not buy the 5 way test. I will get one tomorrow!!

[Watermom]

You can wait until Sunday to shock the pool but ..... if there does happen to be an algae bloom in the works due to your chlorine level dipping so low, your water won't be sanitized. Why don't you do this. Test early in the morning before the sun really gets on the pool. If you have lost more than 1ppm of chlorine overnight from where you are now, you will know that there is something going on with your water and you need to shock. You don't want kids swimming in water that is unsafe. If, there is not more than 1ppm loss overnight, then add enough bleach in the morning to take the chlorine back up to around 12 and let the kids swim. Take a look at the chart at the following link.

http://www.poolforum.com/pf2/faq.php?faq=pool_faq#faq_bg_chlorine

Swimming in a pool with cya of 110 and cl of 15 is no more "dangerous" than swimming in a pool with a cya of 40 and cl of 6.

[Sue225]

got the kit from walmart and ready to shock the pool. Howdo i tell what the chlorine is now. The kit shows 6-8 but the strip show about 3?? Foes the 5 way kit show fc or cc?
PH is Ok, about 7.5 alk is 110-120. I plan to dump 3 1/2 gal of 12%. hows that sound?

[Watermom]

Sounds like a good amount. Add it tonight after the sun is off the pool. Then, test it again early tomorrow morning before the sun really gets on the pool and see how much cl you are losing overnight. If you are losing more than 1ppm, do it again. Try and test/redose at least twice (and more than that is even better) per day until you don't lose more than 1ppm overnight.

Trust the kit over the strips. I think the 5-way kit tests TC. I haven't used one in a long time. Check the instructions.

[Sue225]

If I want to see if chlorine is 25 do i do 1 part pool water and 5 parts distilled water since the test only goes to 5?

[chem geek]

If you mix 1 part pool water with 9 parts distilled or filtered water (water that has no chlorine in it) then you would multiply your reading by 10.

With 1 part pool water and 5 parts distilled or filtered water, you would multiply your reading by 6 (1 part + 5 parts = 6 total parts so 1 out of 6 is your pool water).

[Sue225]

Well i went to ps this am to check chlorine level it was 15 after 3 gal 12%. I added 2 more gal to get to 25! Problem is that it is impossible to measure accurately chlorine level w/o proper test kit and mine has not arrived yet. Strangest thing CYA has been around 100 now the clerk tells me it is 32 in 2 days!! The 5 way test is still telling me cya level is around 100. So, i am just ignoring the clerk, as a matter of fact, i am not going to that store again! Pool is still beautiful, lets see if it holds chlorine! on 6/8 cya was 30 i added the mustard algae junk at that time and within the week it was over the top. 110 with a 1/2 pool refill. Frustrated beyond words. brownish pools of fluffy stuff are still on the bottom of pool. We are vacuuming to grass daily, seems a little better. They seem to settle in foorprints and other indentures in liner. I can't remember my name some days let alone the shade of yellow/orange the shot glass method shows. We guys are the best and i look forward to a lasting relationship with you :) As soon as this pool reaches the point where is holds chlorine i am switching to 6% bleach.

[Sue225]

5 hours and holding chlorine-brown algae is not forming on the bottom of pool anymore, hope i am not getting excited too early!

-------------------------

I have noticed after my husband pointed this out that there is something black in several of the folds of the liner. Is this algae? Will bleach kill it if it is algae? It will not brush out. He said it was there last summer! Just another little something. So you think do you think we should add more bleach tonight? When I do Shot glass method 1 part pool 5 parts distilled water the yellow is a little darker than 5ppm. Thank for your help!!

[Watermom]

it could be algae in the liner folds and high levels of bleach should kill it. But, if it was there last summer, it could be stains?

If you take one part pool water and 5 parts distilled water, and then test with that, you'll need to multiply whatever result you get by 6. So, that should mean that your cl level should be somewhere around 30. If it still seems to be holding at that level, then I wouldn't add any more bleach tonight. Then, try and get out there early in the morning and test (using the dilution method if necessary) and see how much chlorine loss you have overnight. If it is less than 1ppm, then you should be on the home stretch!

You should probably post a complete set of current numbers in the morning. I hope your kit comes soon!

[Sue225]

Kit is here! Readings:
FC 18
CC 0
Alk 160
ph 7.8
Hardness 175
CYA 100

Let me know what you think-pool is clear

thanks

[aylad]

Looks pretty good, except that CYA is awfully high. When you get to the point where you're ready to let your chlorine come down,do NOT let it go below 8 ppm. With a CYA that high, you;'re going to have to maintain it between 8-15 ppm in order not to get algae. This is a long thread, and I haven't looked back yet to see if partial drain/refill has been suggested, but it's still early in the summer, and it sure would be a lot easier to maintain the pool if the CYA weren't that high. DEFINITELY no trichlor pucks or dichlor shock for you!!

Otherwise, TA is a little high and pH is as well, but that puts you in a great position to lower both using muriatic acid. The process is here: http://www.poolforum.com/pf2/showthread.php?t=191

Otherwise, things are looking good!!

Janet

BTW, I deleted the duplicate post--when I moderated your last post in, there were two copies. Since we have to moderate all posts in, if you post something and don't see it show up immediately, wait a bit before reposting--it's probably in the queue.

[CarlD]

If it's a vinyl pool then Alk is not a problem. If it's concrete or plaster or tile, you'll need to lower it.

With a CYA of 100, you'll have to maintain your FC between 8 and 15--you're now a 18 so you are fine.

pH is a little high, but that may be an artifact of the high FC of 18--but it's still in normal range.

About the only thing you should do is wear last year's bathing suits as the higher level of chlorine may fade them.

In short: For a high-CYA pool, your numbers look pretty good. Try adding to drops of the # 7 reagent to your pH test before your add the 0014 reagent. That's chlorine neutralizer and two drops neutralizes about 10ppm of FC--you have nearly 20. You may get a lower pH.

If your TRUE pH is lower and you have a vinyl pool, AND you are willing to maintain a high CYA pool, then I think you are just fine and good to swim.

[Sue225]

Thank you all for your help. I am waiting for chlorine to drop to about 8-10 before I let grandkids swim. I have owned this pool for 23 summers and I never, ever had anyting like this happen before. Grateful you were here to help!
Aylad I have already drained 1/2 of the pool about 1 week ago!
It has been in the low eighties and high ninties here with a few storms. Can you make a guess as to when my chlorine will drop to around 10?
Have a blessed day!

[aylad]

Aylad I have already drained 1/2 of the pool about 1 week ago!

I know that you drained a good bit--but the CYA numbers that you've posted are still very high. So you'll either need to drain/refill some more in order to lower it, OR keep your chlorine levels high (8-15) in order to compensate for it. Which decision to make is yours--I don't know how feasible they are to you.


Can you make a guess as to when my chlorine will drop to around 10?

I would say by late today or tomorrow. It doesn't take long after a rainstorm!

Janet

[Sue225]

If you have cc does that mean something is trying to bloom? My FC is now down to 11 and cc is .5 We had bad storms yesterday and I have not had a chance to vacuum bottom of pool. Do you think that is why my cc went up to .5 from 0?
Thanks for all your help. I have learned so much about pool chemistry!!!

[Watermom]

The rain probably dropped some debris in the pool which can cause a little CC. As long as you are no higher than 0.5 you are ok. Or, you can go ahead and shock the pool and that will take care of it.

[Sue225]

CC was o this AM!!! My test vial was dirty. Washed and dried it and cc was perfect!

Question is my fc is now 8 i do not want it to go lower. How much chlorine should i add tonight to get it up to 11 since i am losing about 3 ppm each day with this heat and sun.
thanks in advance

[Watermom]

In your pool, each quart of 6% bleach should add approximately 1ppm of chlorine. So that makes it easy to know how much to add --- 3 quarts.

[StevenB92]

I slightly remember years ago I read somewhere that if the pool is calm for a while that the CYA will "float" to the top and then you can remove that water, e.g. via the skimmer, thus removing a higher concentration of CYA. Also I believe that the article/post/whatever it was suggested siphoning off the top while having a water hose in the bottom of the pool slowly adding water and "pushing" the higher concentration CYA water towards the siphon.

About a year ago a co-worker told me a pool store guy verified the idea that the CYA will stratify in a calm pool and that to remove the most CYA let the pool settle and then remove the water from the top.

I have been meaning to test my water with the pump running for the "normal" cya level and then after letting the pool sit overnight test the water from a couple inches and then a couple of feet down to see if there is any difference.

Anybody else hear anything similar to this?

[aylad]

First time I"ve heard of it....but my pool is very rarely calm so it wouldn't matter! :)

Janet

[waterbear]

I slightly remember years ago I read somewhere that if the pool is calm for a while that the CYA will "float" to the top and then you can remove that water, e.g. via the skimmer, thus removing a higher concentration of CYA. Also I believe that the article/post/whatever it was suggested siphoning off the top while having a water hose in the bottom of the pool slowly adding water and "pushing" the higher concentration CYA water towards the siphon.

About a year ago a co-worker told me a pool store guy verified the idea that the CYA will stratify in a calm pool and that to remove the most CYA let the pool settle and then remove the water from the top.

I have been meaning to test my water with the pump running for the "normal" cya level and then after letting the pool sit overnight test the water from a couple inches and then a couple of feet down to see if there is any difference.

Anybody else hear anything similar to this?

I have heard that and I have also heard the opposite, that it sinks to the bottom and it is removed by shutting off the skimmers and opening the main drain. I have heard these conflicting stories at product trainings put on by manufacturers that I attended.

BTW! I can tell stories about some of the slight of hand "demos" that I've seen at these too, like the one that 'proved' that MPS makes chlorine 'reappear in the water --glass of tap water which will have chlorine, add OTO so it turns yellow, stick in finger which uses up the chlorine so water turns colorless, add a pinch of MPS (non chlorine shock) and yellow returns but NOT because the chlorine reappeared ad the trainer (who was president of this particular product company!) said but because OTO will turn yellow in the presence of any oxidizer and is not specific for chlorine!)

Is it any wonder that many pool stores give out so much misinformation? Most of what they learn about water chemistry comes from 'trainings' like this!

Getting back to CYA, both are false. Once CYA dissolves it exists as an ionic species in the water and will be evenly distributed as cyanuate ion through out the water. It's basic chemistry!

[Sue225]

My pool liner is puckering like crazy and idea why? I read somewhere that damage can be done to the liner if Ph is too low. Mine was 6.? for a week or so. Do you think it will last through the summer?

Thanks in advance.

[aylad]

pH getting too low WILL pucker the liner--is it on the sides, or has it started on the bottom? I would measure your pH and adjust it to 7.2-7.8, ASAP--as far as how long it will last, I have no idea--depends on whether any water has gotten behind it, in what shape the seams are, etc. You'll just have to adjust your water chemistry and hope for the best!

Janet

[Sue225]

ph has been 7.5 since I started this thread, than to you folks. The puckering is only on the sides. We also patched a hole at the top of the liner this year.
Ph 7.5
Alk 130
Chlorine 8
can't measure cc because I am waiting for more regeant to arrive. I ordered the wrong stuff instead of 0871 I ordered R-0002 DPD Reagent #2!
Water looks great!

[Sue225]

PS I got my cya down to 85-90!!

[aylad]

PS I got my cya down to 85-90!!

Yay!! :D :D :D

Now at least it should be more manageable. Your other numbers look good to me--hope your liner holds the rest of the season!!

Janet

[Sue225]

After lots of rain and vacuuming to waste then refilling, my CYA is down to 50!!
Last night I vacuumed to waste and cleaned the bottom of the pool, backwashed, then shut the pump off. This AM the pool was crystal clear with nothing at the bottom of pool. After 2 hours of filtering this AM I noticed the brown stuff gathering again. So, I am thinking that the problem is the filter. I am going to add DE this PM or, do you think I should flock?
You people are the best! I don't think in all the years I have owned a pool, my pool has been better balanced and beautiful! Thanks again

[aylad]

You can always add a little DE if you want--just enough to make the pressure rise by 1 ppm--and it may help filter out smaller stuff. Don't forget that the pressure rise takes a few minutes though, so add it slowly.

I don't think adding floc is going to help--it is designed to make smaller particles that won't settle to the bottom stick together so it will settle. Sounds like yours is settling fine, so there's no need for the floc.

Good job getting the CYA down to 50--now just maintain your chlorine in the 3-6 ppm range. Actually, I would keep it on the upper end of that, but it should be easier to maintain your pool now.

Janet

[CarlD]

You can always add a little DE if you want--just enough to make the pressure rise by 1 ppm--and it may help filter out smaller stuff. ...

Janet

Janet means 1 psi, not 1 ppm. (Pound/square inch, not parts per million).