Adjusting chemistry with 100% water replacement

[PoolDoc]

Hi CPO;

I think I'm the only one regularly on the forum with much experience operating commercial pools successfully, so I'd better take lead on the responses.

I'm assuming that you've peeked under the cover, and that the water is still clear?

If so, I'd use bleach or dichlor to add at least 10 ppm of chlorine BEFORE you remove the cover. Pools that have wintered without circulation can have an active population of of bacteria and more when opened, and can turn green in hours!

Bleach would be safest, for your liner. But, bleach typically doesn't keep well. Bleach stored since last year might be 1 - 2% chlorine. Clorox brand household bleach stored cool might do better since they filter for metals, which catalyze decomposition. But take a look before you use it. If it's discolored, flush it, a gallon at a time, till gone.

If you use dichlor, dissolve it first. (Wear old clothes and shoes, along with glasses, when you do!)

Get a new K2006C, ASAP. You WILL need to know CYA levels!

Get a copy of your local pool code, and learn it. Go over your last few inspections to find out what your inspectors focus on. Find our what the allowed pH range is, and the maximum chlorine level. THEN find out what sort of violation HIGH chlorine is. In this state, pH violations, and HIGH chlorine are "2 point" violations, meaning points off but no re-inspection and no enforcement action. This is critical for me, since I normally run pools at higher than code chlorine levels. Also find out what allowed CYA levels are, and what kind of violation it is. For a commercial pool without an onsite operator, high CYA + high chlorine can allow 1x per day dosing . . . if the violations are just 2 point violations.

Do NOT use baking soda to raise or maintain pH -- use borax. As it accumulates, it will help with the algae. But you'll get some strange looks the first time you leave Walmart with 25 boxes of borax!

You asked what levels to shock to? With no CYA, I'd limit my first shock to 10 ppm. After than, the answer I'd give depends on your codes and what you're comfortable with. I shock to 10 - 15 ppm in the evening, with CYA levels > 60 ppm, so when the swim team is in the following AM they may be in 10 ppm water.

You'll need to have enough bleach or dichlor on hand to shock to 10 ppm nightly till you get CYA in the water. And, you can't really add CYA till your pool is clean enough so your DE filter can run 3 days without cleaning. Once that happens, add your CYA carefully to the skimmer, so it can dissolve out on the filter.

Find out where your feeder is in the pool circulation loop. If it's downstream of your filter, that's good, since that will allow you to add chems to the skimmers, and not have to worry about the effects of undissolved chemicals reaching the feeder.

. . . . that's probably enough for now.

Ben

[cpoplsc]

Checked the chemistry tonight.

pH 7.0
Chlorine -- 0
TA 90
Ca 260

The water is clear. Some scum/algae at water line (at corner that cover has cut straps). The chlorinator is after the DE filter. I missed the pool store but I have a fair amount of shock (calcium hypochlorite), some pucks (tri-chlor), soda ash and baking soda. The water level is below the skimmers so I can't start the pump until water is added (pump is very touchy w/ air). It will take 4-5 hours to add enough water. I'll see how long I can hold off on pulling the cover tomorrow while we are working on the filter. It is supposed to be cloudy and rainy. The pump is disconnected from the filter.

I'll prepare to shock as soon as we get the pump running.

[Watermom]

cpopisc -- Just wanted to welcome you to the forum and also to thank you for becoming a subscriber. We appreciate the financial support in keeping the website alive.

Question for Ben --- even if his bleach has lost its potency, couldn't he just go ahead and add it to the pool rather than flush it? My thinking is that it would add maybe a little chlorine and it wouldn't hurt anything and it would get rid of it. Correct me if I am wrong.

[CarlD]

It should be brine, which shouldn't hurt. It can still be tested for potency. Somewhere around here I have have the "recipe". I think it's 10 ml added to 10 liters of un-chlorinated water (5 soda bottles) gives you the same dilution as adding 1 gallon of the stuff to 10,000 gallons of water. Then you can measure the FC level in the 10 liters and it will give you the concentration...3ppm means 3%.

Carl