New Pool - Crazy Chemistry - Need Help!

J Level

Mar 29, 2021
Tucson, AZ
Bought house with pool a few months ago - managing a pool is new to me. Has been winter season (in Arizona, unheated) - so hadn't done much with it (adding a stabilized chrlorine tab here and there every week or so). Water has looked really good/clear. With swimming season coming around, I got water tested at pool service shop about two weeks ago with following readings:

FCL - 21.3
TCL - 21.3
PH - 7.0
ALK - 44
Hardness - 677
Iron - 0.0
Phosphate - 4135
Calculated CYA - 158

Over a week or two (not altogether) added Alk Up, Chlor reducer, and NoPhos. Totally removed floater with stabilized chlorine. I am brushing bottom and skimming very regularly. New pool readings as of readings today...

FCL - 23.35
TCL - 23.35
PH - 7.3
ALK - 96
Hardness - 677
Iron - 0.1
Phosphate - 3585
Calculated CYA - 149

Not sure how FCL/TCL got higher, with removal of tabs. Pool store person is saying that CYA takes forever to come down on its own, and that would always need to run chlorine level super high for free chlorine to be effective. No signs of algae. Recommended more Chlor reducer - and potential to need to drain pool. Maybe prior owner super chlorinated to keep looking pristine for home sale? Also, there is industrial strength phosphate reducer (last round was residential/less concentrated stuff). So, looking for advice if should just drain and start over (pool store has draining service, or could look to perform self), keep trying add-ins, or something else?



TFP Expert
LifeTime Supporter
Apr 16, 2007
Pool Size
Salt Water Generator
SWG Type
Jandy Aquapure 1400
Welcome. It is highly recommended that you get a TF100 from and start testing yourself. You have an extremely high CYA level and the pool needs to be partially drained to fix that. Please read the ABC's of pool water chemistry in Pool School to get started.
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Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
Bedford, TX

You are just flushing money and all your "magic" chemicals down the drain... We don't believe in doing that, so we never recommend things like Chlor Reducer, NoPhos and any other Pool $tore magic..

The only way to fix High CYA is to drain.. This will also help your high CH level..

Ask yourself this.. Does it make any sense at all to add things to a pool that you have to drain?? Of course not, unless you operate a Pool $tore.

I suggest you take a long read through our Pool School Pool School - Trouble Free Pool and see what we are all about..

Self testing your own pool water, and learning how to personally take care of your pool, is what we are all about!!


Jim R.