Need help-High Cya, calcium, and algae

I am new to learning about pools and am trying to get the constant algae out of my pool. Last weak in trying to learn about my pool I found the PS website and learned just enough to be dangerous. My ph was 6.8 and my TA was about 60. My pool is about 20k gallons. Anyway, I started adding borax to get the ph up and kept watching the TA to make sure it was okay. After adding 16 lbs. of borax over a couple of days, the ph went to 7.2 and the TA to 80. I started using bleach and kept using the trichor tabs I already had.

After more reading, I realized my test kit was probably too old and did not have reliable readings. I got a new kit and tested to find the ph at 7.2, fc at .5, TC at 1.0, TA at 150, Calcium was over 500 (stopped adding drops thinking I was doing something wrong), and CYA is way high- not even close to the first mark.

I took the trichor tabs out and dumped in 5 lbs. of 55% chlorine shock. What should I do next? I figure I need to get the CYA level down and the CH down as well while keeping chlorine levels high to get rid of the algea (not sure about the stained walls)

I have a sand filter by the way which has low pressure and low flow. After reading on this site, I now think the impeller on the pump must have some blockage.

Thanks for your help,

Greg

Hi, Greg,

It appears you've got a good grasp of your issues...here's what I would do.

1. Fix the pump....the pool needs a good pump just like we need good hearts.

2. Simultaneously with fixing the pump, I'd get a bunch of Cl in there. Tell us what kind of pool you have before we recommend a dosage.

3. The best fix for a pool with the CYA and CH that high is to drain at least half of it and refill. Test and be prepared to drain half again. That should get your CH and CYA down to manageable levels.

Good work on the pH. As I said, you've got the idea...you just need a plan of attack.

I have an in ground concrete pool. I guess that is a plaster pool?

What about that brown stain I can't get off the walls? Is that a form of algae that can be removed without redoing the walls of the pool? If it is permanent, I would just as soon drain the whole pool and fix everything at once.

Thanks,

Greg

Well, from this distance, it's pretty hard to tell what that stain is.

I agree with draining the whole pool ,clearing the stain and starting with new water. That'll be your simplest, possibly least expensive path.

Turbo,
The stains on the plaster could be a result of a number of things... I know some minor staining I had cleared up after a couple times of shocking the pool water and minor brushing. That was from decaying leaves, etc over the winter months and not from algea. Depending on the cause of the stain some sort of scale/stain remover may work. If you are going to drain the pool then you could acid wash the plaster to remove staining. If it isn't that bad I would see if it clears up this season with chlorine and brushing and then if not explore more intensive fixes in the fall.

Thanks for the help everyone. CYA is about 160. I guess draining the pool all the way and scrubbing the sides might be the ticket. I haven't had a chance to research acid washing the sides. What chemicals should be used and what is the best plan of action? Should I consider refinishing the sides?

One last question. I have some leftover sodium dichloro-****. Does this have any stabilizer in it? I know the trichloro does but not aware of the dichloro. I definitely don't want to put any more CYA in the pool unless I have to.

Thanks,

Greg

dichlor is the other stabilized chlorine, your non stabilzied chlorines are sodium hypochlorite (good old bleach!), cal hypo, and lithium hypochlorite (expens$ive stuff!)

I assume acid washing is done with muriatic acid. What mixture do you use and what effect does this have on the bottom of the pool while washing?

Greg

I drained the pool and it appears that the stains are not really stains. I think it is yellow algae that is growing in the crevices and round pocket holes you can't reach. Even so, I tried applying ascorbic acid and then scrubbing it to no avail. If anything, it bleached the area some from the natural white wall color (looks a little greyer to me).

I would then assume that once I get the pool full again with the correct ph, TA, CH, and CYA, I can keep the chlorine levels up to get rid of the algae.

Greg

Greg,

Your assumption is correct. It will probably take some persistence to eliminate that yellow algae but consistent high levels of Cl and frequent brushing will do the trick.

Yellow algae is frequently misdiagnosed. Google the term and you will find some pictures to help you confirm.