Shock creating sediment

Karis

Gold Supporter
May 28, 2018
35
Moorhead, MN
Chlorine
Liquid Chlorine
Hello! We fought mustard algae last year and again when we opened this year. It appears to have cleared up & all is balanced, but when I shocked the pool Saturday night with Cal Hypo (and brushed immediately afterward), I woke up to a ton of fine sediment on the floor of the pool that also had some dirt attached to it. Everything I've read on this site so far says not to use store-bought shock, but why would the pool store tell us to do it weekly if we end up vacuuming to waste every week? Should I stop shocking & just keep the other chemicals balanced? The algae fight might kill me if I have to keep it up. No one else I've spoken to in my region has had this issue with shock. Thanks so much for any input.
 

tim5055

Mod Squad
TFP Expert
LifeTime Supporter
May 11, 2014
11,188
Franklin, NC
Welcome to the TFP pool! :splash:

We find that many times pool store employees primary goal is to sell stuff, not necessarily get your pool in perfect condition. As to whether that is because of improper training, lack of knowledge or just to sell stuff I will leave up to you. While you would think that a "professional" would be the best, unfortunately in most cases it is quite the opposite. Between employees who blindly trust the word of chemical sales representatives and high school kids working in the pool store for the summer you end up with poor results from their advice and testing.

To know what is going on with your pool we need accurate test results we can trust, and those don't come from a pool store. We base our pool care system on your personal accurate testing and only adding what the pool needs, when it needs it. To do that you need your own accurate test kit. Order a TF100 test kit.

The only other real option for a test kit is a Taylor K-2006-C. Be careful comparing prices because the K-2006 comes in sizes, designated by a letter. The basic K-2006 has .75oz bottles. You need to get the K-2006-C to get the larger bottles that you want. Even then it is a little short on the reagent & powder for the FAS/DPD test.

While entirely optional, I also have the SpeedStir and Sample Sizer. They speed testing and accuracy.

I have my suspicion that you have never eliminated the algae from your pool, but only and Overnight Chlorine Loss Test.

How much Pool School have you read? Start with these:
ABCs of Water Chemistry
Recommended Pool Chemicals
How to Chlorinate Your Pool

So, welcome to TFP!!
 

Karis

Gold Supporter
May 28, 2018
35
Moorhead, MN
Chlorine
Liquid Chlorine
Hi tim5055, thanks so much for your input. I had done some of that reading but not all, so I did that and ordered a TF100 test kit. Here are my results from yesterday (6/22/18):
FC: 5.5
CC: 1.5
TC: 7.0
CH: 200 ppm
TA: 240
CYA: 70

Everything is looking good but I haven't added chlorine for at least a week & it's been hot. I had been using pucks and I haven't shocked since my first post in May. Today I bought some 10% liquid chlorine but since it seems that all is fairly balanced, I haven't added anything. We're going to pick up soda ash tomorrow, but in your opinion, are we doing ok? Thanks again!
 

shingles

Bronze Supporter
Jun 12, 2017
271
Houston, TX
Hi tim5055, thanks so much for your input. I had done some of that reading but not all, so I did that and ordered a TF100 test kit. Here are my results from yesterday (6/22/18):
FC: 5.5
CC: 1.5
TC: 7.0
CH: 200 ppm
TA: 240
CYA: 70

Everything is looking good but I haven't added chlorine for at least a week & it's been hot. I had been using pucks and I haven't shocked since my first post in May. Today I bought some 10% liquid chlorine but since it seems that all is fairly balanced, I haven't added anything. We're going to pick up soda ash tomorrow, but in your opinion, are we doing ok? Thanks again!

CC at 1.5 is high. The general consensus here is that if CC is above .5, you’ve got something brewing. You may want to consider stop using pucks and just liquid chlorine. Those pucks will keep raising your CYA, leading to the need for higher and higher chlorine needs. You may want to check out pool school and do a SLAM.
 

Karis

Gold Supporter
May 28, 2018
35
Moorhead, MN
Chlorine
Liquid Chlorine
Mike, I had the pH at 7.5 and CYA was 60 so I started the SLAM today. The chart showed to shoot for 24 FC but I just tested now (about 2 1/2 hours after I added almost 2 jugs of liquid chlorine) and I'm at 29 FC. I used the Pool Math to determine how much bleach to add. Think I'll test one more time before bed & then tomorrow before the sun comes up. Agreed? Thanks.
 
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