Forum Title: Chlorine monster eating all my chlorine....
So I yanked the cover off of my pool last Saturday (05/09/15) and got all of the holes unplugged, filled the water to skimmer level, and got the equipment running. Checked the levels using the TF Testkit, and got a lot of expected numbers, including 0 FC. I dumped about 3 jugs (121 fl oz each) of 8.25% Clorox bleach in the deep end and let it mix for a couple of hours. almost immediately after adding bleach, the water turned neon green, kind of as expected since my well water has high-ish levels of manganese and iron in it. I used a metal sequestrant and continued to run the filter. I later tested and got the following numbers. FC = 9 CC = 0.5 TC = 9.5 TA = 140 pH = 8.5+ (very purple) CH = ??? (did not test) CYA = 35 I did another round of chlorine, TA, and pH tests about 3 hours later, and found the following. FC = 5 CC = 0.5 TC = 5.5 TA = 140 pH = 8.5+ (very purple) So added 3 more jugs of chlorine, and boosted FC to about 14. That was at about 8pm, so that was my last test for the night. I came back the next morning and tested. FC = 14 CC = 0.5 TC = 14.5 TA = 140 pH = 8.5+ (very purple) Absolutely zero overnight drop and very little chlorine drop on Sunday. I started working on lowering TA and pH and dumped in a gallon of Muriatic acid. However, I kept the chlorine level at SLAM level around 14 since no one was going to be using the pool, and I just wanted to be sure about clearing out any algae blooms. I used about 4 gallons of muriatic acid over the course of Sunday, but pH barely moved, but TA dropped nicely to 110. Sunday to Monday overnight drop was zero again with an FC = 14 in the morning. I went to work and left the pool for the day on Monday and came home to find the FC level had dropped to 2.5 during the day and chlorine seems to be hemorrhaging now. Monday was actually pretty cloudy, and temps never went above 70F. I did a drop test last night and found I lost about 1.5 ppm overnight. FC went from 13ppm to 11.5ppm. Test results this morning. FC = 11.5 CC = 0.5 TC = 12 TA = 110 pH = 8.5+ (very purple) Am I fighting an algae bloom, or is something else going on here? Could the combo of the metal sequestrant plus the muriatic acid be killing my chlorine? Water color is currently crystal clear to the bottom of the deep end, with a small amount of dirt on the bottom. I've vacuumed the pool once and brushed twice since opening. Also, I backwashed maybe five times since opening. I have a 26k gallon gunite plaster IGP with DE filter that uses 4.8 lbs DE. Not sure about pump name and HP. This is my second season as a pool owner. Water was crystal clear and algae free all first season. Any help is much appreciated!
Post By: TYRONE MCCARTHY (Brooklyn Park, MN), 02/24/2019
Welcome to TFP! Your PH definitely needs to come down to about 7.4 first. I see you have started this. Remember your PH will also read false if your FC is over 10.
I noticed that I was basically always chasing my pH level all last season. I thought maybe this was normal for a plastered gunite pool. Seemed like I was adding about a gallon of muriatic acid per week, so having relatively high pH wasn't too much of a shock to me. However, the fact that my initial TA was at 140, I figured it made sense that pH was at least a little high.