Increase FC residual to offset poor circulation

[waste]

Hey Ralph!

You're on the right track for keeping algae at bay with frequent testing. I have to test the pools 3X/ day. This allows me to track chlorine loss and combined chlorine rise and dump some liquid chlorine accordingly (when it's below 1 ppm, I add enough to get it to 2+) .

Where the poly comes in is when I find algae spots in one of the pools. I dose with the 2X treatment, after I've shocked and brushed and maintained a fc level of 3 for at least a day - I make sure that there is no visible algae , then add a little less than what they call a 'weekly' dose, every other week. It's worked for me and i hope it will for you.


I'm always willing to talk about pool care with you.

[chem geek]

Yes, when one has a pool with poor circulation in an area and one doesn't want to have a much higher chlorine level to try and compensate for this, then using Polyquat 60 is an option as is using 50 ppm Borates. These are algae inhibitors with the least amount of side effects.

[ralph]

Okay- getting to specifics do you have any recommendation as to the amount of polyquat 60 vs additional chlorine? It has been an exasperating summer, used many gallons of bleach but perhaps my technique is flawed. Do you have any recommendations for me?
desperate Ralph

[chem geek]

Following the dosing recommendations on the bottle of Polyquat usually works well. If you have visible algae growth, start with 16 ounces per 10,000 gallons and then use 3 ounces per 10,000 gallons weekly. Unless your pool is very large or you lose a lot of water from backwashing and splash-out, you may find that using 50 ppm Borates is more economical as it is mostly a one-time cost. For example, for 10,000 gallons, the maintenance dosage of 3 ounces Polyquat costs around $1.80 per week. 50 ppm Borates in 10,000 gallons would need 7-3/4 76-ounce boxes of 20 Mule Team Borax @ $2.50 each plus 282 fluid ounces (2.2 gallons) of full-strength Muriatic Acid (31.45% Hydrochloric Acid) @ $5/gallon so about $30 one-time cost. Or you could get 24 pounds of Boric Acid @ $27.75 per 15 pounds so about $44. Again, this assumes 10,000 gallons so scale up or down accordingly.

[waste]

I just add the start up dose and then supplement with the weekly dose.

With the pools I care for, I have to check combined chlorine every day - if I see it start to rise, I add a gallon of 12.5% and then add the suggested bi-weekly dose of poly a few hours later (having brushed the low circulation areas).

The other solution I had, before using the poly was to brush the low circ areas daily, while maintaining < 4 ppm fc limit max that law requires for commercial pools.