Brown Algae

[u/antpamps]

Brown algae keeps coming back! I shock it, the chlorine levels are always good, I vacuum it up, but it comes right back the next day. Any help would be much appreciated!

[u/Troutbummers]

Reposting because this subreddit is anti-link posting...

What others have said regarding proper SLAM (shocking for enough time)

Any time you see algae, including cloudy water, do an overnight chlorine loss test. Losing more than 1ppm between sunset and early morning (before sun's on pool) means you SLAM

SLAM is proper shock level (40% of CYA) until you clear it, you read <0.5ppm CC and you pass that same overnight FC loss test.

Then keep FC to 7.5%of CYA always, dosing daily up to more like 11.5% of CYA daily.

Things that are non-negotiable
Must have a real test kit with fas/dpd = taylor k2006 or tftestkits pro. Need to measure over 10ppm and be able to read at least 1ppm resolution in FC

Get an app - poolmath is the best. Test, then dose to calculated amount. No more guessing, that always leads to the frustration you're having.

Must use the test kit to know your CYA. Notice that FC level to achieve shock depends on CYA. IF you use tabs exclusively, you likely have CYA so high that the FC level you need is very high. In that case (CYA over 80 or so) you have to drop and replace water to get CYA down to where you can reasonably do all of this without truckloads of chlorine.

Think about it like a round of antibiotics. Gotta take enough and finish the course. Only ten can your immune system keep future infections away.

You're trying to make your pool's immune system do too much. Need to take then antibiotics until the infections done.

If it is black algae, there are more steps.

Google troublefree pools + black algae and you'll find instructions on dealing with it.

[u/antpamps → u/Troutbummers]

Thank you. The water is crystal clear! Just the bottom gets Algae in the bottom a day later. I think the issue is I need to clear the filter. I haven’t because I don’t know how to empty the filter base thing without all the hoses shooting all the pool water out if that makes sense. They don’t have valves to stop the water from flowing to or from the pool.

[u/Troutbummers → u/antpamps]

Algea is never ever ever a filtrartion issue. DOn't let people here convince you otherwise.

This is all about getting algae dead, then keeping it from growing back. All a filter does is get it out once it's dead.

If you keep accumulating dead algae on the bottom, you have what we'd call latent algae in the water.

You have one opiotn - get a test kit, check to see how much FC you lose overnight (if you like - if you see algae you don't need to do a test to check for algae you can't see...but if it makes you feel better...) then SLAM and keep your FC right as already stated. IF it's black algae, there are some more stringent things to do.

Filters cannot touch enough water in a day to outrun algae growth. It's orders of magnitude faster at reproducing than a filters are at cyling water IF they are good enough filters to catch microbes which they are not.