I see draining in my future

[Praterma2]

Hi guys! Excellent BBS!
Just bought a house here in AZ with an in ground pool. I know the previous owner used pucks to chlorinate and was very hands off. My test results (using the tftestkit) came back with the following results:
FC 9, CC 0, TC 9, TA 160, pH 7.5, CH 680, CYA 120 or so, temp 50
I figured the CH of 680 was caused by being in AZ, and high CYA was caused by using the pucks. I see no algea growth yet, and the water looks good but as things warm up, I am guessing I'll have problems. Should I go with an RO service, so I'll be able to tackle both the CYA and CH problems at the same time? Or just drain and fill? Advantages/disadvantages? I'm a chemist in the real world, so feel free to go technical if you wish.
Thanks!

 

[JasonLion]

Welcome to TFP!

You seem on top of the issues already. The tradeoff between water replacement and an RO treatment are mostly a question of RO being available in your area or not, and the relative cost, in cash and eco impact, of the two approaches. This time of year is usually fairly good for water replacement, as CH levels are usually lower in the winter. Still, RO doesn't waste anywhere near as much water and is usually price competitive. Both RO and replacing water will lower both TA, CH, and CYA, though not by the same percentages. RO reduces everything uniformly, while water replacement tends to reduce CH and TA less, as there will be some CH and TA in the fill water.

If your fill water CH level isn't too high you could get by with a water replacement of 50% or less, relatively minor compared to what can be required in other cases. That might tilt things towards water replacement, though it will take some phone calls and a little calculating to see which is actually less expensive.

 

[thunderkyss]

What is RO?

With a 120 CYA, & a clear pool, he haste using an algecide right?

Also, the FC of 7, is that doing anything with the 120 CYA?

 

[PoolGuyNJ]

RO is Reverse Osmosis. It is a way to purify water for nearly any and all things in solution.

Scott

 

[Guest]

R/O is available in Gilbert (www.calsaway.com), so that is a viable option for him. I don't think it should be so much of a decision of which is "cheaper", as much as it is water quality and conservation. Those that use a SWCG do not do it because it is cheaper, but for the convenience and ability to control their water better. Utilizing R/O, especially in AZ where they have high CH and lots of evaporation, makes it a win-win for the customer in terms of better water than they would get from a drain and refill and less chemicals required. The savings in water is just a nice side benefit.

I'm biased, of course, but I understand the benefits from using R/O where available. I don't see the benefits from a drain and refill, especially where water is hard and gets harder quickly, because of high temps and evaporation. The R/O company can give you back sub 200 CH and allow for quite a while before you would need the service again. In the meantime, you would use less chemicals from having "purer" water, and enjoy a "softer" pool than the drain and refill could provide.

 

[Praterma2]

I have a RFQ (request for quote) for RO. I have not tested my fill water yet, but that will probably define which way to go (that and the cost for the RO). I will keep you guys updated. Many Thanks!

 

[Guest]

Good for you You are fortunate enough to be in an area where this is an option. Always good to check all of your options and make the decision that is best for you. Good luck!