Using TFP SWG Guidelines

[JackR]

Learned a great deal by reading through the posts here. Hoping to understand a bit better some of the specific guidance in the Water Balance for SWGs post.
This is my third season owning a pool and my second maintaining it myslef (the pool service company I used the first season was revealed to be a real crook).
My water is clear but there is some brownish staining on the sides and on the floor of the deep end of the pool. My latest test results from the local Leslie's is:
FC:4 pH:7.4 TA:110 CYA:55 CH:240 Salt:3400 Phosphates:750
I already ordered a K-2006 and should have it in a couple of days. I hope to test the FC at dusk and dawn to determine whether there is an algae presence.

Comparing that with the recommendations in the Water Balance for SWGs post I should be looking to:
Maintain FC
Raise pH slightly to 7.5-7.8
Lower TA dramatically to 60-80
Raise CH dramatically to 350-450 for plaster
Raise CYA to 70-80
Maintain Salt

Questions:
1. The Lower Total Alkalinity post says "You shouldn't lower TA just to reach a target number". Considering how much higher my reading is over the recommended level, should I make an effort to lower TA?
2. Similarly, do I really need to raise CH above 350? The Hayward CHEMISTRY QUICK START GUIDE recommends a range of 200-400 without differentiating between pool types.
3. I Based on what I learned here so far I understand that I should not increase CYA until I am sure that the staining I see is not algae, because if it is elevated CYA will require more chlorine to treat it.
4. I already own Kem-Tek KTK-50-0006 Pool and Spa 60-Percent Concentrated Algaecide. The instructions say to add after super-chrlonating to FC 5. Any thoughts on whether this could hurt?

Any help and advice would be much appreciated.

 

[needsajet]

Welcome to TFP! Good to have you here and thanks for doing the reading and coming up to speed before posting. Much appreciated

Best to wait to make decisions until you have reliable numbers from the K-2006.

The TA and CH can wait until after any algae is eliminated. But just for info sake, SWGs usually cause upward pH creep, which can be slowed down by keeping TA lower. To keep the water balanced for the good of the plaster, recommended pH and CH are a bit higher to compensate for the lower TA. Both TA and CH are OK for now and can be fine-tuned later.

And yep, you've got it, keep your CYA down until you know whether or not you need to SLAM.

You can try holding a vitamin C tablet against a stained area and see what happens. If ascorbic acid lifts or significantly lightens the stain, it's iron. You could also try a chlorine puck or tablet in an old sock for 10 or 15 minutes on a stain in the bottom, and if you end up with a clean spot there, it's probably algae. You might want to ask the pool store to test for copper and iron. We don't generally rely on pool store results, but for those two it's better than nothing.

Someone will know if that's polyquat 60 algaecide. If so, you could hang onto it for closing the pool.

 

[JackR]

Thanks for the reassurance on the TA and CH.
I tried the vitamin C test - but on the advice of a local pool guy I used a lemon instead of a tablet and didn't see results. I'll try to get a copper and iron reading from Leslie's tomorrow.

Also forgot to ask about the phosphate reading. I've read on these boards that it doesn't matter as long as my FC level is maintained, but since i also have a full 3L bottle of PhosFree extra strength I'm wondering if/when I should throw that in.

I'll post my new test results when the K-2006 arrives.

 

[JackR]

Update: I had water tested at my local Leslie's again and while there was no read for copper/iron, there were some other surprises.
New readings are:
FC:0 pH:7.5 TA:120 CYA:30 CH:250 Salt:3500 Phosphates:1000

I'm assuming that the FC going to zero is because there is still some algae in the pool, but how/why did the CYA cut almost in half?
BTW, my SWG is set for 100% and I have it running 13 hours/day.

 

[isriam]

your pool store probably doesnt test properly, thats why. get your test kit and do it right.

 

[Schadenfreude]

It's OK to put some bleach in there to help your SWG out if it's struggling to keep up.

 

[chiefwej]

It's impossible for the CYA to be half of what it was, unless you have drained half of the water and refilled. That tells you how much you can depend on pool store testing. It's worth just what they charge...nothing. When you have your own dependable, repeatable test results, you can begin to make the adjustments needed. Until then you would be working blind.

Other than making sure you SWG is working and/or dumping some bleach in to insure some level of chlorine, there is little you can do without accurate test results.

 

[JackR]

I was afraid that unreliability of pool store testing would be the consensus.
I'll add some bleach and hold off until my kit comes in.

 

[needsajet]

In case it's helpful for future reference, for your 35,000 gallons, the Hayward T-15 replenishes 2.6 ppm FC at 100% and 13 hours. There's a good chance that will keep up once the organic contamination is killed off. As mentioned for big swim days and hot, bright days, supplementing with liquid chlorine will be helpful.

I don't think the phosfree is needed, but it's also not harmful. I would wait until the algae is killed off before using it up.

 

[JackR]

Thanks. The T-15 calculation is very helpful.
I'll stock up on some more liquid chlorine (the Ocean State Job Lot in my area has Austin's 1 gallon "shock" (12.5% Sodium hypochlorite) for $2.99).

 

[needsajet]

Excellent, that sounds like a good deal. It may have a manufacture date code on it. An example would be 16180 with the 16 meaning 2016 and the 180 meaning the 180th day of the year (late June). Grab the freshest jugs to get the best value