Pool Algae Problem after storm

[reggie]

Hi there

We have just renovated a pool that hadn't been used for over 10 years re grouted new pump new electrics etc. Got it working beautifully and Crystal clear since beginning of July. We have had some rain a storms which raised the PH level but kept in in check using minus ph and the all in one tablets. and all has been good. Until

Then last week we had really bad storm and high winds which deposited a lot of debris in the pool. so we cleaned it out cleaned the filters (skimmer and pump) and started to sweep the walls and floor. This created some green clouds which we thought would just either get filtered out or we could deal with the vacuum. Only its just gotten worse. in space of 2 days we now cannot see the bottom of the pool and its green. Chlorine levels are high and PH are low. we have tried everything from more chlorine, anti algae fluid. minus PH. more all in one tabs. Cleaned the filters again, backwashed the sand filter, had pump running 3 days solid nothing seems to be working!

Help

[Teapot1]

Your all in one tablets contain a chlorine stabilser CYA (cyanuric acid) when you rely on them totally the level reaches very high and you loose control of your pool, just as you report. Its no good saying chlorine levels are high we actually need the numbers and most importantly the CYA figure and not from dip strips which are very very bad and innacurate. A proper test from a good pool shop if you havent got a good test kit yet.
Switching to liquid chlorine or HTH shock is your best bet but you may need to drain some water and replace with fresh if your CYA is too high, hence why we must have the numbers. If you have to go to the pool shop for a test ignore anything they say and dont purchase anything except liquid chlorine or HTH shock. Dont mix HTH shock with other forms of chlorine that would be very bad and could explode. It is ok once its in the water.
Report back when you can and we can begin to help clear up your pool. Oh and welcome to the forum

[reggie]

Many thanks for your reply. I am not relying in the 5 in one tablets i just have them in the pool to help. I have been testing chlorine and PH levels regularly with a testing kit and adjusting PH levels down and adding chlorine granules as needed. and up until the bad weather it has been Crystal clear. I have never tested the CYA level as i dont have a tester. thats my next purchase. Also ill try and get some liquid chlorine and or HTH shock. I assumed my chlorine granules would be sufficient? at the moment the ph and chlorine levels are as follows. PH about 6.8. chlorine level is weird. My testing kit has a yellow liquid but when i put the 5 drops in it has gone a very dark orange colour? (i did put a lot of chlorine in yesterday to try and shock) i did add some anti algae liquid yesterday as well. this morning pool has improved a little , not much! yesterday i couldnt see the bottom from the shallow end. now i can just see the bottom from about a meter. My next plan was to buy some floculant and try that?

[Denniswiseman]

Don't buy the flocculant as Teapot says get a test for CYA
Excessive CYA renders your chlorine ineffective and you have to use more to get the same sanitation
For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm
To reduce your CYA you have to do a partial drain and refill
Continuous use of Trichlor/Dichlor will raise your CYA which means you have to raise your chlorine level as well

[Teapot1]

I wouldn't specifically say dont buy flocculent, used correctly it can help speed up the clearing of the water by clumping (flocculation) of the stuff together but it needs to be done correctly. However testing first as Dennis said is the most important part.

Your test kit is the OTO test, it tests for total chlorine not free chlorine. That could show for example you have 6ppm of total chlorine but you would not know that the free active part may only be 3ppm meaning you have 3ppm of combined chlorine which is the smelly swimming pool smell we knew as kids

[reggie]

HI there quick update unfortunately i cant source an CYA kit here in Bulgaria. however i used a floculant a couple of days ago which seems to have helped. Swept up the crap a couple of times and it has cleared a little. PH levels 7.5 and chlorine is still somewhere between 7 and 10

Pool is no longer green but its not as clear as it was 2 weeks back. Still cloudy but blue in colour. guess its just a matter of vac / backwashing / vac and keep on top of the ph until it clears? i really dont want to go down the route of half emptying and re filling at this point in the season, probs only 3 or 4 weeks left at a decent temp.
any more advice would be welcome!

[Teapot1]

Ok you are doing well its a time thing and you cant buy that so keep up the good work and the chlorine level and brushing.
Try and find a better test kit.

[reggie]

update

We finally got around to fitting a summer cover for the pool. We have now been vaccing and backwashing every day for a week checking lvls etc but every day when we take the cover off there is a thin layer of brown sediment at the bottom. its like a very fine brown powdery dust? it vacs away easily but its back the next day. so now im thinking the filter isnt working or maybe the wrong sand? (we replaced the sand at the beginning of the summer) any suggestions? ive tried everything from altering the valve positions for skimmer and main drain and constant backwashing. any suggestions would be welcome!

[Teapot1]

If you are vacuuming through your skimmer then scrunching up a fluffy cotton towel into the skimmer basket will generally catch it all. Sand cant catch fine particles without assistance from a good clarifier like jolly gel. I dont know if you can get Dr Drydens AFM ng but that is the best filtration media you can get, filters to 1 micron without flocculent and below that with flocculent.

[reggie]

Many thanks will give that a go tomorrow!