Installed new salt water filter in the pool this year. Finally got it clear in late May, but late June pool had brown stuck to bottom. Vacuumed out shocked Pool turned cloudy, put in "Pool first aid".
Water was milky, and brown silky residue in water on bottom. Brown stuff would just float away when vacuuming, like trying to sweep flour from the kitchen floor. So we completely drained the pool and started refilling.
Partially filled that night and it looked great, next morning after finished filling the pool still looked great and shocked with chlorine the brown stuff is back and keeps multiplying. Pool water test is perfect. Pool is 18'X48" round intex pool- w/Sand filter. Pool people
Thanks for the question Sue
I'd like to have your complete chemical readings, the actual numbers:
Chlorine, CYA (cyanuric acid/stabilizer), pH, Alkalinity, Calcium Hardness, and Metals (iron and copper) and names of any algaecides you may have used along with clarifiers, phosphate removers, and/or flocs. It makes troubleshooting much easier.
Pool First Aid is a combination of enzymes to help break down organics and a clarifier causes small particles to clump together so they are easier for the filter to catch and backwash out. I'd only use this as a last resort as it can get expensive to use. It also doesn't tell why your pool has this issue. It's kind of a Band-Aid on the problem.
It's interesting that, according to the question, the water turned brown right after shocking. Is that correct? Brown water after shocking can indicate high metals in the fill water. Are you on well water? This could be the issue. If this is the case you'll need to use a good metal sequestrant. Metal sequestrants that are based on HEDP, phosphonic acid and/or its derivatives are the most effective.
Some popular brands are Jack's Magic Blue, Purple, and Pink Pink Stuff, Metal Magic, Metal Free, & Metal Klear. This is normally not a one shot deal. A metal sequestrant does not remove metal from pool water. It holds it in solution until it can get filtered. Then you backwash the metal out. Because metal sequestrants break down over time and get filtered and backwashed out, you will need to add a bottle once per week.
I should have mentioned that it is brown algae I have in the pool, whether that makes a difference to the way I treat it. The water looks a lot clearer now after treating it.
I would like to thank you for replying to my question from a few days ago, it was very helpful. I am being fanatical with the cleaning of the cartridge, and the pool itself and I am running the pump constantly but in the mornings I am still finding the brown sand on the bottom and sides of the pool, although greatly reduced.
My question is-it may appear to be stupid, but is the algae dead or alive ?
Thank you for the compliment Raelene. I'm glad your pool is clearing up. There are no stupid questions, just bad advice from people who call themselves "pool guys". Algae is alive when it first occurs in the pool but when you do a good pool shock the chlorine kills it.
Also be sure your cartridges are free of any tears or rips. Anything like this and the dirt, debris, and algae will just go right back into the pool. This is one trick that I use when I sweep the pool at the YMCA. I temporarily turn off the filter so no water is circulating. Then I gently sweep the walls and floor of the pool. This allows the debris and dirt to fall to the bottom. Once the dirt settles a bit I turn the filter back on and either gently sweep the debris to the bottom drain or vacuum it up.
By turning off the filter for a few minutes it allows the dirt to settle rather than hitting the water coming out of the returns and being blown around the pool. There are some brown algaecides on the market but I would first do the above. Once you keep your chemicals in line there really shouldn't be a need for anything else.