High Alk, Low ph


Active member
Jul 2, 2020
New fiberglass 16000 gallon pool with 600 gallon spa, Pentair equipment and IC40 SCG.

Since getting it shocked and cleaned up I've been trying to get everything balanced, but my alkalinity has been so high it has been out of range on the test strips I've been using. After about 1.5 gallons of Muriatic Acid, the alkalinty is down to about 150, but obviously ph has been dropping as well, reading at 6.8 now.

Just out of curiosity I tested my tap water (water source) and sure enough it reads with the crazy high alkalinity as well.

What I have read says that even soda ash will raise alkalinity a bit so I'd rather not use any unless I have to. I have a 15" drop from spa to pool and have been running the system spilling over to try to aerate the ph up as much as I can.

Salt is 3200
FC is 3
TH is 100
CYA is 30

Any input on where to go from here would be greatly appreciated. Thanks.

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
Texas, San Antonio/Marion, South-Central Area
Pool Size
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
Welcome to TFP! :wave: Right now the best thing you can do for your water is get a TF-100 (link below) or Taylor K-2006C test kit. See Test Kits Compared. Test strips are absolutely horrible and your numbers are probably much different that you expect. I wouldn't do much adjusting to anything except FC right now to ensure you keep algae away. See our FC/CYA Levels. Once you get one of those test kits, post a full set of numbers as listed below and we'll be happy to help.

Have a happy and safe 4th! :salut:
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