Help with pool

[tim665214]

About a month ago my pool turned green. I have been fighting with it since then. (And spending lots of money). I am so excited that I found this site last week. However, I just got my K-2006 test kit, so I am now able to post real numbers. Through the use of heavy shock (Trichlor) I was able to get my algea under control. However every morning when I go outside, I still have small spots of algea around the outside of the pool. I vacuum to waste, but then the next day they are there again. About a week ago I took a test to my pool store and they told me my cya level was 145. I drained about 18" out of the pool and refilled, then my cya was 115. After vacuuming to waste a few times and backwashing once, here are my numbers from yesterday at the pool store:
FC 3.37
PH 7.8
CAL 101
TA 167
CYA 60
I do not see how my CYA level could have dropped from 115 to 60 with just backwashing and vacuuming. (I started using plain bleach to chlorinate about a week ago also.

Here are the first tests from my kit this evening
FC: 5.2
CC .2
PH 8.0
TA 225

I added 1/2 gallon of muratic acid to try and get my ph down. I am waiting for that to distribute in my pool, before I do a CYA test from my kit. Once I do a CYA test, I plan on shocking with bleach to whatever level is needed based on CYA level.

One other thing, I have city water, but I live in a rural area. I tested my source water and got the following:
FC .8
PH 7.7
TA 280

The TA level of my source water is VERY SCARY!!! What can I do about it?

This is the summary of my situation. Sorry it is so long, but I wanted to cover everything.
Am I on the right track? Any help would be appreciated.

Thanks

Tim

8300 gallon AG pool. (not Intex) 22" sand filter. 1.5 hp motor running on low.

[tim665214]

I just re-tested after adding muratic acid, and circulating my pool and here are the results
FC 4.5 - concerned that this went down by .7 after dark.
PH: 7.1
TA: 180
CYA: 80

I am about to take my FC up to 20, and check it in the morning.

[tim665214]

Can anybody help? I am not sure where to go from here. Last night I took my Chlorine level up to 20. I checked every three hours today and added bleach every time to keep my chlorine level above 20. (It seemed to drop about 1ppm every 3 hours). This evening though there was a thin layer of algea over the entire bottom. It vacuumed up real easy (I vacuumed to waste) but I am not sure where I go from here. I am waiting on the pool to fill back up to its normal level, then I am going to do another test.

Any suggestions would be greatly appreciated.

Thanks

Tim

[Watermom]

With a CYA of 80, take the chlorine on up to 25ppm. You need to continue to keep the chlorine high until you can go from sundown one day to within two hours of sunrise the next morning without losing more than 1ppm of chlorine, you don't have more than 0.5ppm of CC and your pool is clear. Brush the pool daily after you add the bleach. Try and test as often as you can as you are doing and each time, take the chlorine back up to 25.

If your pH drops any, add a little Borax.

Hope this helps.

[tim665214]

I just tested the water after vacuuming and re-filling. My FC level is 16. When I did the CC test I added the first set of drops, and if I were to glance just right at the sample, I could barely make out some pink. (10ml sample) I then added 1 drop of the first reagent, and the water immediately cleared up completely. So I would guess that my CC is .1 or .2 (If anything) I did a ph test and it showed 7.4, but I thought I had read that at high chlorine levels you can't trust the ph test. Correct?

Anyway, I am about to take the chlorine up to 25 ppm, and test first thing in the morning to see if it held.

Thanks

Tim

[tim665214]

This morning I tested my water about 30 minutes after the sun came up, and FC was at 25.5. I just tested again and my FC is reading 24.5. (After being in the sun for about 4 hours) So I think it is safe to say that chlorine levels are holding. Also, I am not seeing any algea on the bottom of the pool. I am going to start letting my chorine level come down to around 9 or 10. (I measured my CYA level twice, and it seems to be between 80 and 90.)

Does everything sound ok? If I happen to see a little bit of algea this evening, could it be what I was unable to vacuum yesterday that just settled down, or would it mean that I definitely still have a problem? I don't think my CC is at 0, but it is definitely less than .5

Also, when would it be ok to test my ph again? How low do I need to let my FC level drop before I can get a good reading?

I think I am on the right path, but any help or assistance would be greatly appreciated.

Thanks

Tim

[tim665214]

This evening when I checked my pool, I didn't see even a trace of algea for the first time in a while.

I held my pool at 25 ppm all day yesterday, and this morning I tested, and saw that it held all night. Also my CC is almost 0.

I noticed my FC level tonight was 16.5. Which means I dropped about 8 ppm today. Does this seem right? My CYA level is between 80-90 and I live in N.E. Texas where the temperature today was 105. (No swimmers today) Hopefully I will not lose 8 ppm every day.

Is chlorine loss linear depending on level? For example, all other things equal, if I start out at 24 and lose down to 16 in a day, would I lose down to 2 if I started at 10 that day?

If anybody can offer any advice/tips I would really appreciate it. This has been a long battle that I believe I am at the end of, so I don't want to do anything that would cause me to have to start over.

Thanks

Tim

[PoolDoc]

Hi Tim;

It's hard to judge whether your pool's chlorine loss is above normal or not, till you have been able to hold things stable for a while. In general, chlorine loss seems dependent on the CYA/CL ratio + pH more than on absolute chlorine level. BUT, chlorine demand can be fast or slow, depending on what the source of the demand is. For example some components of urine are oxidized slowly, and will continue to exert chlorine demand for quite some time after the 'incident'.

In fighting algae, one very important factor to keep in mind is that it's not over till AFTER you think it's over. In other words, keep brushing and keep the chlorine high for several days AFTER there's no detectible algae. Also getting in the pool and feeling for 'slimy' spots can be a very effective 'early warning' method in vinyl pools.

I'll get back to you later today, with some more info.

[tim665214]

Thanks for the advice. This morning my pool still looks good. No visible algae. I tested this morning and my FC is 15. With my CYA level between 80 - 90, this is too low for a shock level, and too high for a normal daily level. Should I take the chlorine back up to shock level for another day or two? Currently my pool is holding levels overnight, and I would guess CC is around .2. (With a 10 ml sample I put the drops in for a CC test and the sample barely turns pink. And then I add just 1 drop of the next re-agent, and it immediately clears up. So it is definitely less than .5)

Since I live in a very hot area of the country, I am thinking I want my CYA levels around 75. But until my levels drop to that from splash-out and backwashing, I plan on keeping my daily chlorine level at 9. Does that sound right? (Current CYA 80 - 90)

[PoolDoc]

Your plan sounds OK (FC=9; CYA=90), but yes, I'd recommend keeping the chlorine high for several days after all trace of algae is gone.

Also, I'm working on a project that will allow all subscribers to log their pool readings via a smart phone or net device (it's a page, not an app), AND have their dosing info auto calculated for THEIR pool. I'm just starting on what you might call 'beta' testing today. If you are interested, email me at poolforum@gmail.com You don't have to have a smart device to participate, however.