Cal-Hypo dispenser

[vincent]

As my recently filled water are low in CYA (Est. 20) and CH 60, I need to get both of them up. I am on both Trichlor and Cal-hypo. If my FC can hold at 3 by sunset (which seems to be doing quite well), I intend to concentrate on Cal-hypo to get my CH up.

Under normal application, it's best applied everyday or at least once every other day, right? But my being away from home all day (weekday) make it very inconvenient to dsipense Cal-hypo regularly so I decided to make a temporary dispenser to slowing add Cal-hypo when the pump is running. I dump a week's Cal-hypo in a plastic bottle and hang it over my waterfall. Adjust the flow rate to a trickle thus adding slowing. But the whole lot of Cal-hypo is soaked under water in the bottle until dissolved .

Now the questions are:
1) will there be any adverse effect to the soaked Cal-hypo for more than a week before dissolving and got mixed with pool water?
2) Though the mixture may not be very consistent ( I would expect the flow rate and mixture concentration to vary some 10-20% from reloading to finishing of Cal-hypo, would there be any problem if I try to maintain a slightly higher FC to offset any variation in flow/concentration?
3) with the Cal-hypo under water before dissolving, will the chlorine lost it's strength? There are two chambers of water all the time (upper chamber consist of pool water and some chlorine mixture and the lower chamber the water with dissolved chlorine and undissolved Cal-hypo). The inlet and outlet are both at the top.

This is only a temporary setup to last about 4 months just to get my CH up.

Vincent

 

[chem geek]

Though you can use Cal-Hypo to raise the CH, you can also just add Calcium Chloride pellets to raise it immediately. I suppose if you've already bought the Cal-Hypo then that's a sunk cost so you might as well use it. In the meantime with the CH so low, I'd keep the pH up higher (7.8 to 8.0 until the CH starts coming up and assuming your TA is around 100) just to minimize any plaster corrosion that might occur over an extended period of time. Normally when refilling a pool, one uses Calcium Chloride to raise the CH level in which case you wouldn't need to raise the pH.

By the way, your fill water should have no CYA in it. If you are measuring CYA, then this is what was left over from the last draining of the pool since CYA sticks a bit to surfaces including pool plaster and pipes.

As for your questions, having the Cal-Hypo pre-dissolved in the bottle should not be a problem unless the bottle is not designed to contain a strong oxidizer such as chlorine. Maintaining a somewhat higher FC is not a problem unless it gets really high or if you don't have CYA in the water -- which you don't have very much of right now so I would be a little careful about that. With the Trichlor, for every 10 ppm FC you'll add 6 ppm to CYA so you'll get some CYA in the water reasonably soon. The Cal-Hypo in the bottle should not lose its strength except maybe getting a little diluted as it runs out. Essentially, it sounds like you're trying to simulate what The Liquidator does. Personally, I think it's a lot easier to just use Calcium Chloride to get the CH where you want and be done with it.

Remember that Trichlor is very acidic so be sure to keep the pH up by adding Arm & Hammer Washing Soda or 20 Mule Team Borax (the former raises TA more than the latter -- you didn't say what your TA level was). You definitely don't want the pH dropping with your low CH as that combination would get you into an even more "corrosive to plaster" situation.

Richard

 

[vincent]

Thanks Richard for your speedy reply.

My #s FC3, CC0, pH 7.8, TA80, CH60, CYA 20, Temp 80, Salt 3300.

Where I live, no stabilizer (CYA) and Calcium Chloride available except chemical laboratory use grade. Thus I am using pool grade chemical in other form to slowly get what I need and it's a new pool with pipe water fill. Will switch on my SWG only after my CH and CYA are normal.

Richard, while you are here, does it matter very much if I got Borates? My ph had always been stable since 3 months ago. To date I've not been able to get borate in whatever form. My SWG specified FC1-3, CH 200-300, pH7.2-7.8, CYA 40-60 and TA100-120. You are the expert on this, crunch me some numbers. Thanks.

Vincent