Persistent Yellow Algae and High CYA

[Gene1939]

I have been struggling with yellow algae for some time.
In mid February 2022, I did a back flush, then removed, disassembled and cleaned the grids of my 60 sq ft filter and canister with chlorox.
After re-assembly of the filter & adding DE, I applied yellow out per instructions, & using HTH calcium hypochlorite shock.
But the algae persisted. The algae streams into the pool while the pump is on. So, I did another such a filter cleanup in May 2022.
Algae persisted. I suspected the chemistry was off. A HTH test strip read as follows: FC-0, ph-7.8, TA 180ppm, TH-600-800ppm, CYA-150-300ppm.
I removed the 3" trichlor tab floater from the pool and shut down the pump assuming I now have a chlorine lock due to the high CYA.
Thus the high CYA was limiting the chlorine's ability to kill the algae.

Reducing the CYA by water replenishment is a problem during a drought here in southern California and the chemical reducers of CYA appear to have poor reviews.

Any suggestions would be appreciated. Thanks, Gene1939

 

[Wobblerlorri]

Welcome to TFP!

First of all, you need a proper test kit. Strips are notoriously unreliable. Check out this link Test Kits Compared for the kits we recommend.

Everything in our method of pool care hinges on using a recommended test kit and liquid chlorine to sanitize. I would encourage you to add 3 ppm liquid chlorine daily until your test kit comes.

When you get your kit, run a full complement of tests and post in the following format

FC
CC
pH
TA
CH
CYA

Then we can help you. Also fill out your signature so we can better help you.

 

[Rancho Cost-a-Lotta]

Welcome to TFP Gene!

Most of us end up here after messing up our pools in one way or another. For me, I was relying on the pool store to test my water and recommend chemicals. Big mistake! What I ended up with was CYA so high I had to run super high chlorine levels to keep it sanitized, stains from tabs and shock on the surface, and some real good 5-gallon buckets for car-washing.

For the price of a couple bottles of magic potions from the pool store, you could invest in a TFP recommended test kit (Test Kits Compared) and take control of your pool. The TF-Based kits are the best value for the residential pool owner.

If you've been using solid forms of chlorine and shock, your chemistry is likely out of whack. We are here to help and can walk through the process step-by-step.

Spend a bit of time in Pool School to learn the basics. Here is some light reading when you find time.

Pool Care Basics Archives

Your one-stop shop for all things TFP to include: ABCs of Water Chemistry, Recommended Chemicals/Levels, Test Kits, Troubleshooting, and much more!

www.troublefreepool.com

Best wishes!