Draining to Lower CYA

Jump to latest Follow Reply
N

Nitedr

0
Aug 28, 2014
17
West Covina, CA
Hi Guys,

Been lurking for for about a week now and finally decided i had to post.

Just moved in to our new home a week ago and got started on the pool. Pool was previously maintained by a pool guy. He did a poor job. DE filter without a multiport valve so I can't backwash. I'm going to have to remove the filters and hose them off. Current pressure at 15. Hayward pump runs for about 8 hours a day. I'm also using the Aquabot I used at my old house.

Water is crystal clear but here are the numbers:

FC - 11.8
PH - >8
CYA - 360 (After diluting sample, this number may be off)

I am going to drain about 85% of the water on Monday (Weekend vacation). My question is..... Do I have to slam the pool once filled even though I don't have an algae problem?

FYI.... I'm going to be using Chlorox Bleach, Borax, and Baking Powder. Some conditioner if the level drops below 30 after refill.

Thank you guys in advance. This forum rocks.
 
You should do an OCLT (overnight chlorine loss test) to see if you have organics. With that CYA and the fact that it hasn't been getting a lot of attention I would be surprised if you didn't need to SLAM.

Are you sure it is a DE filter? Removing the filter and hosing it off sounds a lot like a cartridge filter. Maybe they said they added DE to the cartridge filter and you misunderstood?
 
I performed an OCLT a couple of days ago and my FC dropped from 13 to 11.9. I'll add chlorine tonight and perform another tomorrow morning. I've been trying to keep FC around 13 until I actually drain and fill.

Definitely a DE filter. It's a Pentair FNS Plus. Whoever installed it, probably the old pool guy, didn't bother to throw in a multiport valve.

Last week, old pool guy knocked on my door to offer his services and part of his sales pitch was that he would replace my DE Filters once a year and add conditioner before summer and after summer. It was at that point that I knew he had no idea what he was doing. When he came by he did mention that it had been a week since he last serviced the pool. Pool wasn't neglected but was treated with something that raised the CYA through the roof.
 
Update.... Starting draining around 8:30 p.m. on Sunday night. Drained about 80% and then started filling at about 2:00 A.M.

Wife finished with the fill this morning. Just got home and tested chemistry with the following results:

FC: 1.5
PH: 7.6
TA: 210
CYA: 60

CYA was still a little higher than what i was shooting for (50) but it is much more manageable than the over 400 it was at before draining it. Added the MA and Chlorine Liquid (518 oz) to bring it up to SLAM level of 24.

Just one question. I was low on MA so I didn't input the TA levels into Pool Math. Pool Math said to add 60 oz of 14.5 MA to lower PH to 7.2 but if input a TA of 210 it says to add 129 oz. I didnt want to drop PH too low so I only added the 60 oz. Should I pick up some MA and add the additional 69 oz of MA it suggested?

FYI... Pool is crystal clear after fill and I still don't see any signs of algae. Slamming for precautionary reasons.
 
At this point hold off on MA additions. Above 10 pH you can no longer accurately test. Hopefully it goes quickly. You can do an OCLT tonight to see how you stand. Did you test for CC after the fill?
 
tim5055 said:
At this point hold off on MA additions. Above 10 pH you can no longer accurately test. Hopefully it goes quickly. You can do an OCLT tonight to see how you stand. Did you test for CC after the fill?
Click to expand...

I did not do a CC test after the fill.

Got home from the gym and tested chemistry. FC was at 16 and CC was at 0. Added chlorine and ran FC test about 40 minutes after and got a FC of 23.5, CC was 0. Hopefully I will lose <1 FC PPM and my SLAM will be over. I plan on leaving the pump running until I have a successful OCLT. Sun has been intense in SoCal so I'm going to make sure I'm up before any direct sunlight has hit the pool and burned off any chlorine.

I'll update tomorrow morning after I have tested FC and CC.

Thank you.
 

Enjoying this content?

Support TFP with a donation.

Give Support
Tested this morning and got FC at 20.5 and CC at 0 (Approximately 9.5 hours since last night's 23.5 FC result). I brought the FC back up to SLAM level (24). Will check the FC and CC when I get home this afternoon. I'll add chlorine then and then I'll perform another OCLT tonight.

Thanks again.
 
timerguy said:
Like you said, your diluted cya test was probably a little off. 20% of 360 is 72, so, it may very well have been 300 instead.
Click to expand...

Definitely off. But a CYA at 60 is much more manageable than what I was working with before. I was shooting for a cya in the 40-50 range but I cut it a little short.

I figure with splash out, filter cleanings, and some rain my CYA will fall within the 40-50 range for next season. I want to add borates once I figure out the rhythm my pool.
 
Update.

Tested again when got home from work and got fc at 19 and cc at 0.

Added chlorine and will test when I get home from gym. Sun has been intense all day. I'm hoping that is what burned it off and not something living in the pool.

Will update...
 
Came home from gym and fc was 21.5. I think my volume may be off or something because I added enough to get up to 24 before I left. My pool is kidney shaped so getting an accurate volume is tough.

Added anoth 59 ounces to get it up to 24. Tested after 30 minutes and got fc at 23.5 and cc at 0.

Am I expecting this to be over too quickly? Starting to get a little frustrated.
 
Sometimes it's quick, sometimes not so much.

You should only consider FC levels that you test, not "calculated" levels. While you may expect an outcome by adding a certain amount of chlorine (or other chemical for that matter) you should always test to verify where it ended up. Variables may include the volume as you note, but also the strength of the chlorine you use. It may not be up to it's advertised strength.

Patience will win.
 
Thank you for the advice. I think tested too soon after I put in the chlorine and it hadn't thoroughly mixed.. I stepped out to buy more chlorine anticipating that I would have to add more tonight but when I tested it I got an fc level of 24.5 and a cc of 0.

I'm going to use that for my oclt. I will report back in the morning.
 
I tested this morning when I woke up and got an FC of 24 and a CC of 0. Pool is crystal clear and I have no signs of algae (Never did see any algae but I'm now convinced I had something living in there).

I think this means I'm done with my very quick SLAM. Now on to maintenance.

Thank you to everyone who posted.

Next project..... Borates.
 
Great job!!

Now, if it were me I would hold off on the borates for a couple of months. Get to know your pool and it's needs first. I have considered them but with a German Shepherd Dog and 4 cats that think it's their water bowl I feel it's off the table for me.
 

Enjoying this content?

Support TFP with a donation.

Give Support
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply