Filter not doing the job?

I swear I posted this a few hours ago, but its not showing up so I apologize in advance if it shows up twice.

I've been fighting an algae problem for about a week now. Here are my current measurements:

FC: 15 (this morning)
CC: 0 (this morning)
ph: ~7.7 (this morning)
CYA: ~40 (measured this past Saturday)
TA: 160 (measured late last week)
CH: 140 (measured late last week)

Initially I wasn't too diligent about my chlorine levels due to being busy with life, but I've now had my chlorine at or above shock level (15ppm) for a good 48 hours. Yesterday the water began looking more clear, but after reading the instructions on fighting algae more carefully I decided to brush my pool yesterday afternoon. This generated quite a cloud of green "dust" down in my deep end, which is where I brushed everything towards (because that is where my main drain and skimmers are). Last night I backwashed and topped off with a big bottle of walmart bleach. This morning the pool is still cloudy. I brushed and although I kicked up a little bit of debris, it wasn't nearly as bad as yesterday. I'm discouraged that my filter doesn't seem to be clearing the water because I'm pretty sure at my current chlorine levels I've got the algae killed by now. I backwashed again this morning. Oh, I've been running the filter 24/7 this entire time I've been fighting the algae problem.

One question I have is, how often should I backwash? I've seen both things recommended (not backwashing too often or backwashing daily). I should note that the pressure on my system never seems to change much. It is always around 19 or 20.

Any help is appreciated. I'm heading out to retest my chlorine levels now...

Tested my water last night and FC was 12.5, CC was zero. Added 1.42 gallons of 6% bleach, which should bring FC up to 15. This morning the water was looking clearer. I can see the drain at the bottom of the deep end (~9'). I tested the water again and FC was 13.5, CC zero. I brushed again and there is still some residue (and of course the water is all cloudy again and I can't see the drain in the deep end any more). Does this mean that the algae isn't dead or that it isn't being filtered out? This is so frustrating. I don't seem to be making any progress despite high chlorine levels and running the filter 24/7. Please help!

I'd also appreciate an answer as to how often I should backwash during this process.

Finally, I'm having trouble updating my sig. My pool size is actually more like 34000 gallons and I am using a Taylor K2006 test kit.

Forgot to mention in my last post that I added another 1.42 gal jug of chlorine. I just did another test. FC=15.5, CC=0, Ph=7.7.

Also, as my updated sig suggests, my pool volume is actually more like 27000 gallons. So 1.42 gallons actually raises my chlorine by 3.2, not 2.5, which is what I earlier thought. Assuming that is correct, my morning bleach should have brouth me up to around 16.5 and now I'm 15.5. So I lost 1ppm of Chlorine in a matter of 3 hrs. So I'm thinking the algae isn't all dead after all, which would explain why things aren't clearing up. Does that analysis sound good? (I'm assuming my CYA measurement of 40 from Saturday doesn't need to be redone yet, besides I'm running low on that reagent, but I've got a new batch on order). I'm going to start measuring chlorine every few hours now to make sure it stays above 15ppm.

i dont much about sand filters so i cant comment about backwashing, but keep it running 24/7 like you are untill the mess is cleaned up.

seems odd that you are getting a CC reading of 0 because it sounds to me like you are still fighting algae as you still found "residue" while brushing. also you lost 1PPM of chlorine in 3 hours, so something is using it. you will also need to test at night, or after the sun is off the pool, and then again in the morning within 2 hours of the sun being on the pool to see if you are losing more than 1PPM of chlorine overnight. if you are losing more than 1PPM overnight then the battle is still on!

your CYA wont change much as long as you have not added any stabilized chlorine to the pool or drained a LOT of water and refilled. if you tested 40 last week, then its probably still 40, so save you reagents for now.

this is the most important thing... test and brush often, and keep that FC above shock level AS MUCH AS POSSIBLE untill you are 100% certain all the green stuff is gone. once its all gone you will still be left with a cloudy mess. be patient and as long as your filter is working right it will get cleaned up! it took me a few days to kill off all my algae, water bugs, and tadpoles, ( actually the tadpoles were dead in minutes ) but it took a couple weeks to get clear again!

good luck!

I updated your signature, with your new data. Please note the gallons figure: it's based on a 20x40 pool with a 3.5' WATER depth and a 9' deep end (8.5' water), with a break at the midpoint, and a hopper bottom. If the break is closer to the shallow end than that, OR if the deep end is straight sided with right angle transitions from the walls to the floor, then the volume will be higher.

+ If the algae is green, you need higher levels of chlorine. If the algae is BROWN, then it's dead, and just needs to be filtered.
+ Do NOT backwash too much. Backwash when the filter pressure has increased 5 -8 psi over the clean pressure. (You do have a working pressure gauge, right?)
+ You can TEST your filter with a small amount (~1 lb) of DE powder added directly to the skimmer. If it shoots back into the pool after going through the filter . . . your filter needs work, and you may not be able to remove the algae till the filter is repaired.

I'd say the algae is green, so I guess its not dead. I'll keep going with the chlorine and try to keep it at 15 or above.

I do have a pressure guage but I kind of question if its working properly. It never seems to change. It is always around 19 or 20 psi and never seems to go up. I'm pretty sure it does go down to zero if I turn off my pump.

I'm not sure what DE powder is, but I'll look it up in the abbreviations and figure it out.

Thanks

Just tested my water again... FC=15, CC=0. Adding another big jug-o-bleach which should bring me up around 18. I'll test again b4 bed and maybe I'll add another just for good measure. Will report back in the morning.

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Originally Posted by gogolion

I do have a pressure gauge but I kind of question if its working properly. It never seems to change. It is always around 19 or 20 psi and never seems to go up. I'm pretty sure it does go down to zero if I turn off my pump.

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Make sure it does go to zero. If it IS working, and never goes up, your filter may need more sand.

DE powder is filter powder, diatomaceous earth, used in DE filters. You may be able to get a 5 or 10# bag at a pool store.

The pressure gauge does go to zero when I turn off my pump.

I added another jug of bleach late last night without testing (I didn't see responses to this thread until this morning). I tested late this morning and FC=16 and CC=0. I'm going to add another jug soon to make sure it stays well above 15 (my shock level according to the best guess chart). I've just got to go buy some more. I brushed again this morning and the amount of residue seems a little better, but its still there. I consulted my mother-in-law and we decided the color is a brownish green, somewhere in between. Some areas seem more brown, some more green. Maybe that means its dying but not dead?

I'm also going to go by some DE powder and run the suggested test. How do I tell if my filter needs sand? Do I need to take it apart? Or is there some way to tell without that?

One other thing I may not have mentioned is that my pool leaks fairly significantly through some cracks. I normally top it off every couple of days with a couple inches of water. Today the level was close to bottom of my skimmers. I decided it may filter out more easily if there is less water so I turned off my skimmers and I'm not topping it off. Of course, my pressure dropped to 12 or 13. Is an unwise move? That is, am I better off topping off and running my skimmers or letting it be and turning off my skimmers.

I'll report back after my DE powder test. I'll also start testing late at night and in the early morning to see how much chlorine I'm losing overnight.

One more question... so far I've just been brushing, hoping the skimer and drain would pick up the debris and it would get filtered out. Would I be better off vacuuming? The problem there is that it is so time consuming. Brushing is pretty quick and easy.

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Originally Posted by gogolion

One more question... so far I've just been brushing, hoping the skimer and drain would pick up the debris and it would get filtered out. Would I be better off vacuuming? The problem there is that it is so time consuming. Brushing is pretty quick and easy.

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I wouldn't bother with vacuuming, then, till the algae is ALL dead, AND the filter has been checked. If you vacuum with a filter that's not working well, you can end up just pumping all the algae back into the pool.

Since I had to go to the pool store to get DE powder anyway, I decided to bring a water sample and have it tested. Now I'm thoroughly confused. Some of their measurements don't match mine at all. They say their test equipment uses lasers so its accurate, which I thought was funny. I'm going to take what is leftover of the sample and retest when I have time later today, but here is what they got that didn't match mine at all.

FC = 5.13 (I tested it at 16 4 or 5 hours ago)
CC = 0.07 (I tested it at zero)
CYA = 10 (I tested it at 40 this past Saturday)

Here are the values that more or less match mine:
Ph=7.8 (I got 7.7 this morning)
TA=168 (I got 160 a week ago)
CH = 163 (I got 140 a week ago)

Their suggestion was that I should add a half gallon of muriatic acid to bring my Ph and TA down. They say high TA could cause the cloudiness in my water. Should I listen to them?

I'll report back after I test the same water sample as the store.

Thanks for that set of comparison numbers! We often here of the discrepancies, but don't often get exact numbers.

The results are actually better than what we often hear about. The prescription isn't nearly as bad as some. And, actually, the CC value should be considered equivalent as well. On the other hand, the CYA and FC errors are pretty serious.

I'll go this far: get a gallon of muriatic acid, read the muriatic acid handling guide linked in my blue signature box, and then go ahead and add it, but only 1/4 gallon at a time -- and test the pH 4 hours or so after the addition. Adjust your pH down to 7.2 - 7.4. With a TA = 160, it's going to tend to drift upward. You don't want it wandering way up there, while you are trying to get rid of algae.

By the way, transporting a sample can cause values to change, especially if it gets hot OR if there's any air space in the bottle.

You're right, the CC is virtually the same. I initially was listing all the values, but then decided to separate them and forgot to move that one. The sample did not get hot (it is a mild, cloudy day her in the Chicago area), but there was a bit of airspace. I retested the same sample and got 13.5 for my FC level. I did not retest Ph since it has been steady at 7.7 for the past week. I happen to have a 1/2 gallon of Muriatic Acid so I'll add some and retest later. After testing the sample at 13.5 I also added 2 96 oz. bottles of bleach (walmart was out of the big bottles). I'm going to retest my chlorine in a little while and add more if necessary.

I just tested my water for the night. FC=17, CC=0, PH=7.2. I'm leavng it alone and will test again first thing in the morning.

This morning FC=14.5, CC=0.5, Ph=7.2. Gotta run and get some more bleach. So I lost 2.5ppm of chlorine. I guess this means the algae is not dead yet, huh?

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I was just doing some more reading and came across the sticky about mustard algae. I'm starting to think that is what I have. It is a thin film of "dust" that reappears every day. You don't even really notice it unless you let it build up over days or if you brush it, then it becomes a cloud of dust. The color? I'm not sure. It's sort of green, sort of brown, maybe yellow? It's definitely not a bright breen. My high chlorine levels don't seem to be killing it. Is this what I could be dealing with here?

Quote:

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Originally Posted by gogolion

came across the sticky about mustard algae. I'm starting to think that is what I have. It is a thin film of "dust" that reappears every day. You don't even really notice it unless you let it build up over days or if you brush it, then it becomes a cloud of dust. The color? I'm not sure. It's sort of green, sort of brown, maybe yellow? It's definitely not a bright breen. My high chlorine levels don't seem to be killing it. Is this what I could be dealing with here?

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With a CYA at 10 - 40 ppm, if you chlorinate to FC = 20 ppm daily, and brush after each bleach dump, it should clear up after couple of days. CONTINUE to chlorinate that way, for several days AFTER you no longer see any trace of it.
Sure sounds like it.

I feel your pain,,,,Although I am not an expert like many of the people who are helping you here with the chemical advice. I will say this ...I have way to much experience cleaning up dead algae with a poor working sand filter from the days before I joined the site.

I have found that turning the filter off for a few hours and vacuuming to waste helps get rid of the "dust'. Also when I have the fine dust in my pool I use "skimmer socks' on my skimmer basket. They are expensive and a pain,,,sometimes i would wash them out a couple of times a day. They do seem to help get rid of the small particles.

If you figure out whats wrong with your filter let us know.

Good luck!!!!

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Also when I have the fine dust in my pool I use "skimmer socks' on my skimmer basket. They are expensive and a pain,,,sometimes i would wash them out a couple of times a day. They do seem to help get rid of the small particles.

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fyi, found a 10 pack for $9.75 on Ebay, $3.50 shipping.

thanks I'll check them out!!!

Thanks for the advice. I'll look into skimmer socks. Regarding vacuuming to waste... it takes me a couple of hours to vacuum my pool. That is a LOT of water to be dumping, isn't it? Seems to me I'd have to be filling at the same time and probably wouldn't be able to keep up.

Thats true .....I brush the walls, let the water sit for a few hours so all the sediment settles to the bottom of the pool(pump off) then while filling I quickly vacuum what I can(usually about 10-15 minutes),,,just hitting the heavy areas. Of course this was a last resort only when water was extremly dirty.

I wouldn't do this untill the algae was dead(blue color).

Water is cheep and plentifull here in Ohio....not sure what its like in your area.

As I said before since I started getting advice from this site on how to properly treat my water I have not had any problems.

Thanks everyone!!!

papa

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Originally Posted by gogolion

Regarding vacuuming to waste... it takes me a couple of hours to vacuum my pool. That is a LOT of water to be dumping, isn't it?

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Why does it take so long? We vacuum a 45' x 75' pool in about 45 minutes. Granted, we use a 36" vac head. Do you need a better vacuum system? If you have good suction at the skimmer, this vac head is probably what you want:
Pentair R201286 222 Pro Vac Series Commercial Pool Vacuums

We use the larger model of that head, but you need REALLY good suction if you do. If you are careful, you can vacuum very quickly with that head. Unless your pool is rough, we could vacuum it in about 30 minutes.

Hmmm, maybe I'm not getting good suction.

Is there a way to measure that? It feels pretty strong to me on my hand, but then again I have nothing to compare it to. I think I have a 24" vacuum head and I definitely do not get suction the entire length of the head. I really only cover a few inches wide with each pass of the vacuum. I plug one of my skimmers when I vacuum to get better suction. I guess I'll also try turning off my main drain. One thing I've never understood, which could be a cause of poor suction, is that air always seems to get air in my system when I vacuum. Air is always gurgling out of the returns. I have no idea where it comes from since no air gets in when I am filtering normally. I always make sure my pool is full (middle of skimmers) before I vacuum.

Quote:

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Originally Posted by gogolion

One thing I've never understood, which could be a cause of poor suction, is that air always seems to get air in my system when I vacuum. Air is always gurgling out of the returns. I have no idea where it comes from since no air gets in when I am filtering normally.

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Sounds like a suction leak. If it is, it will probably get worse when you close the main drain. And, a suction leak will definitely impair vacuuming.

However, using a 1 1/4" hose, instead of a 1 1/2" will mess vacuuming up, as well. Also, stiff vacuum heads sit too high above the surface, and not create the high flow / high suction necessary for good vacuuming. The ProVac heads conform to the pool surface much better than any others I've used.

I went to the pool store today to get a skimmer sock. They guy there said the skimmer sock won't catch fine particles such as algae. Instead he sold me some cullulose fiber DE replacement that you put into your skimmer to help your filter grab the fine particles. He said to add it 1 scoop at a time to my skimmer until the pressure goes up 1psi. I told him that my pressure never seems to increase and he said I may need more or new sand. So I went home and after adding 5 scoops my pressure didn't budge. I called the guy and he said add 2 more scoops and if it still doesn't move then I probably have a problem with not enough sand or needing new sand.

Can the kind folks here please give their opinion on the pool guys' diagnosis? If I do need to add sand or new sand is there a guide on this site somewhere of how to do that?

Thanks in advance

Did someone here suggest a skimmer sock for you? They definitely won't remove algae.

Cellulose fiber may gum up your sand, but you can remove it when you work on the filter. Doing so is a pain on top mount filter -- you have to cut the plumbing, before you can unscrew the valve!

There's a good chance your pump is too big for your filter, and has been blowing sand out every time your backwash. You'd have to give us actual pump and filter model numbers to be sure.

Yes, earlier in this thread someone suggested skimmer socks. Luckily the guy at the store steared me away from that.

Here are my model numbers:
Pump: Pentair model SF-N1-1-1/2A/340039
Filter: Pentair Tagelus, Part #145241

Please let me know if they are mismatched.

This equipment was all installed this year by a pool company. I'm probably under warranty if it is malfunctioning or was installed incorrectly.

Pump: Pentair model SF-N1-1-1/2A/340039 = 1.5 HP Pentair SuperFlo (curves)
Filter: Pentair Tagelus, Part #145241 = TA60D 24" top mount sand filter, maximum desirable flow, 45 GPM

To give you a comparison, I run a 36" filter (2x the filter capacity) with a 1.5HP Hayward Super pump which has the same curve as your pump . . . and it is PLENTY big enough, even though it has to run a high restriction fountain!

You'd probably be better off replacing the impeller, diffuser, and seal, and dropping back to 3/4 HP performance. You'd cut your electrical bill by 35% or more . . . and you'd be able to filter fine particles. As it is, you have so much flow and pressure, you just force the fines through the filter!

So what should I do? Call the company that installed the equipment at the beginning of the season and tell them they sold me a pump that was too big? Of course they're going to tell me I don't know what I'm talking about. I'm kind of in a bind here.

Oh and BTW, on the side of the pump it says it is 1.65HP.

If I go to a smaller pump will that give me less suction when I vacuum?

The craziest thing happened yesterday. I called the pool company and they said someone would call me back today. Then last night I went out to add some bleach and I noticed no water was coming out of the returns. The pump was running but didn't seem quite right. I turned it on and off and no difference. Finally, I looked at the pressur guage and it was up about 10 psi!!! So I backwashed and afterwards it seemed to be all working fine. I'm at a loss. The pressure never went up for days and days and then all of a sudden it goes up by 10psi in a matter of hours? Is that normal? I'm so frustrated with this pool I'm ready to fill the darn thing in!

Finally some progress!!!

With the help of my son I've managed to keep the chlorine level in my pool above 17 since last THursday and we've been brushing whenever we add bleach. Yesterday the pool FINALLY looked blue instead of green! Today I can actually see the bottom of the pool in the deep end. I'm going to keep going with the high chlorine levels until the water is completely clear.

Since the water is getting clear I assume my filter is actually working, but I am still seeing 'residue' on the bottom of teh pool every morning. When I started attacking this it was an even layer, but over the past couple of days it seems to have changed such that it accumulates into various areas around the pool into "piles" if you will, rather than a smooth layer. Once the water is clear if the residue doesn't go away I may try vacuuming these "piles" rather than just brushing them up.

Thanks for all the help. I'll try to report back when things are all clear.

Good job! Keep going with the high chlorine levels until the pool is clear AND until you can go from sundown one night to sunup the next morning without losing more than 1 ppm of chlorine, AND your CC = 0. The residue that you're seeing is probably just dead algae, and can either be brushed up so the filter can get it, or when it's over you can just vac them to waste.

Keep up the good work!