Quote Originally Posted by StevenHB View Post
added 3 lbs of granulated CYA last night.
Hm-mmh. Via your skimmer?

Ok -- like this:

1. No more CYA, till you can hold a residual overnight, and your CC is 1.0 ppm or less.
2. FIVE gallons of plain 6% bleach each EVENING through Thursday PM
3. Friday, clean your filter -- you have to get any remaining CYA OUT of the filter.
4. After the filter is clean, make 1,000% sure that there is no trichlor, no ionizer, no NOTHING except pipe and pump between the skimmer and the filter. Note your clean filter pressure.
5. Dose with 5 lbs (6 cups) of cal hypo added SLOWLY to the skimmer. Add the first cup, and wait 30 minutes to see if you forgot something. If there's still CYA in the filter, it will sound like you are cooking popcorn in it -- when the CYA + cal hypo particles DETONATE! Usually, this doesn't damage the filter, but it's MUCH better to avoid this.
6. Repeat EACH evening. Clean the filter by opening and washing it out, when the pressure has gone up 10 psi.

Several comments:

=> If you haven't already raised the pH, per instructions above wait to do so, and let me know CURRENT pH
=> Adding via the skimmer like this, will leave all the calcium from the cal hyp ON the filter. You will have to physically remove it from there.
=> Cal hypo reacts badly with almost everything, except water, borax and soda ash. Do not mess up -- NOTHING between the skimmer and the filter except pipes & pump!!!!
=> Following this process will actually REMOVE calcium from your pool water, at the cost of your having to clean your filter more.

BUT there's a next step, involving washing soda. I need to hear from you on this stuff first, however.