algae control with high stabilizer

[thespian49]

my pool seem to show algae every couple of days n shocking seem to help for a day, the pump pressure seem to build up to a point needing backwash every few days! what do I do to correct this problems?

[Watermom]

What kind of pool do you have? What is the volume?

Do you have current water testing results taken with a drops-based kit that you can post?

Tell us specifically you have added to the pool meaning ingredients and not product names or 'shock.'

Repost with requested info and someone here will try and help you.

[thespian49]

in ground pool with a chlorination. readings: TH 400,F Chlorine 3/6 (3), PH7.5, Alk 150, Cya 120.0 not added anything lately.

[Watermom]

How did you get a CYA reading of 120? With it that high, you are getting algae because you are not keeping your chlorine high enough. Take a look at the Best Guess Chlorine Chart in my signature below for more about that.

With high CYA and the high chlorine levels you will have to run, you need a kit that can measure chlorine higher than 5ppm. Order a Taylor K2006 or 2006C. Link in signature. (Won't be available locally.)

What are you using for chlorine? No more trichlor tabs or dichlor powder. They have CYA in them and yours is already too high. Better to just use plain unscented bleach.

Welcome to the Pool Forum!

[thespian49]

I use 6 way hth test strip n also take the water sample to the pool store they tend to match most of the time. Can I use 'Pool Brand' Algecide 40 to control this problem? It seems to create foam in the spa water! On using simple liquid bleach (sodium hypochlorite, 6%) can I directly add it to the skimmer? It has been raining for last two days n the afternoon test was cya 100, fc 0, th 100,ph 7.2 ta 80.

[PoolDoc]

Do *NOT* use foamy algaecide; it's not really effective and it's not really chlorine compatible. Instead, do these things:

1. Purchase a cheap OTO / phenol red kit (yellow / red drops).

2. Purchase 10 gallons of PLAIN 8.25% household bleach for each 10,000 gallons of water in your pool. Purchase 1 gallon of plain *DISTILLED* water (not spring, not bottled, not artesian: "distilled"!).

3. Read the Best Guess page, linked in my signature.

4. Add 4 gallons of bleach per 10K gallons of water.

5. Brush the pool, and make sure the pump is running 24/7

6. Test the water with the OTO kit. If the result is not VERY dark yellow -- darker than the test block shows -- add 3 more gallons. KEEP the water in the DARK yellow range. KEEP the pump on. Test the pH by mixing 1 cup of pool water with 1 cup of distilled water, and testing that mix. (High chlorine messes up the pH test; adding distilled water dilutes the chlorine, but changes the pH by only a tiny bit.

7. Meanwhile, order a K2006 test kit -- link in my signature block.

8. Test the CYA level as soon as the K2006 arrives. (Test strips are ESPECIALLY bad at testing CYA!). Since the CYA is probably high, test a mix of 1 cup pool water + 1 cup of distilled water. This does affect the reading, so multiply your result x2.

9. Re-read the Best Guess page and determine your correct chlorine level, for your CYA level. Use the K2006 FAS-DPD to adjust your chlorine level. Then, test with the OTO -- if you can recognize the color, you can use OTO for 'quick' testing, to avoid using up your FAS reagent too quickly.

10. Oh, yeah. Do NOT add ANY more pool store stuff: not algaecide, not phosphate remover, not clarifier, not flocculant -- NOTHING. If you need to RAISE the pH, use borax. If you need to LOWER the pH, use muriatic acid. (See safe handling page linked in my signature.)

Good luck!