Restarting after draining

jimvr4

Member
Sep 17, 2007
8
San Jose, CA
Hi All,
I had been having alot of trouble with yellow mustard algea after years of trouble free operation. I was using a feeder with Trichlor pucks since the pool was built in 1998. In 2005 I started having trouble with mustard algea. Leslies recommended draining and refilling due to excessive TDS. Of course the trouble returned since I continued to use the pucks. This year I was constantly getting mustard algea and buying Leslies Yellow Out which worked but only for a short time. My search for answers brought me here where I learned about CYA saturation. After that I had Leslies test the water and they recorded CYA of 90 on one test and 150 on another. They tried to sell my wife the power powder and Phosfree again but I told her to just get the test results. A couple of weeks ago I drained the water way down to relieve the CYA level. Upon refill I was able to hold FC of 20 ppm overnight. My current numbers are:

FC 7.5
CC 0
PH 7.5
TA 90
CH 120
CYA <30

Since CYA is off scale right now I decided to add pucks to the chlorinator for the time being. How often should I test the CYA level while I'm trying to bring it up to 30-50 (I don't have SWCG)? Also should I add calcium? One of the problems I've been fighting is white streaking on my rosa flagstone under the spa spillway. I spent last Saturday scrubbing with a 60/40 muratic acid solution which helped but not enough. Sunday I refilled and shocked. The pool water is clear since the refill.

What would you guys do now?
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,880
Silver Spring, MD
CYA will go up by somewhere between 1.5 and 3 for each trichlor tablet you use. So I would retest the CYA level after perhaps eight tablets. Keep in mind that trichlor tablets will lower the PH and TA over time.

Since you have a plaster/gunite pool your CH level is rather low. I would aim for CH somewhere around 300. You will get some white staining anywhere water evaporates on the stone, but they should develop quite slowly. There are some chemicals you can add to reduce how much that happens, but people have had mixed results with them.
 

robrinker

LifeTime Supporter
Aug 2, 2007
178
Northeastern Ohio
I would think the most cost effective way to add calcium would be to chlorinate with Calcium Hypochlorite.

My wife got a 50lb bucket of 48% Calcium Hypochlorite from BJ's Wholesale Club (which is like a Sam's Club) for something like $48. I'm not sure how much of that you'd need to get your CH to the recommended level.

Any of the experts can chime in and correct me if I'm wrong.

Since we are on the subject, would 48% add more CH per bucket than 65%?
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,880
Silver Spring, MD
43% cal-hypo typicaly costs around the same per pound as CH Increaser but it adds half as much calcium per pound. There is value to the chlorine it includes which balances out the cost disadvantage, but to take full advantage of that requires using it slowly (at the rate your pool needs chlorine). Note: the lower the percentage the less calcium you get.

Place like Home Depot/Lowes/WalMart frequently have the best prices, but they tend to run out of things this time of year. Other than that try Internet pool supply places for deals.