Test Results on a Slightly Green Pool

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krsnaday

0
May 31, 2017
15
Mountain View, CA
Hello,

I got my TF-100 kit this afternoon and I know you're supposed to have the pump running for a bit before testing, but I was too excited and only ran the pump for 25 - 30 minutes before testing.

Here is what I got:

FC = 33ppm
CC = 0
TC = 33
CYA waaaaaaay below the lowest gradation on the cylinder. If the 100 mark is close to the half way point, mine was less than quarter of the column.
( I guess that means the CYA is high? )

I didn't measure Ph but when the pool guy came on Tuesday he showed me it was around 7.4 or 7.8. I'll measure again tomorrow and post.

This is a pool that I inherited that has apparently had an algae problem and I definitely see it when I brushed the pool again this evening. Cloud of green from the wall.


What should I do next?
Increase CYA and then SLAM??

Thanks a lot !!
 
Additional dilution causes pretty significant errors and at this point you know you are over 200+ CYA. You now know you need to replace a lot of water to reduce your CYA level. At 200+ your FC of 33 isn't even close to SLAM, you would have to get up to 100 FC to make a dent in your current situation. Obviously that really isn't feasible.

Unless you want to go to the expense of reverse osmosis treatment (which is likely available to you being in CA) your only solution is to replace a significant portion of your water to reduce your CYA level.
 
Well you want to drop your CYA down below 70, so if you were to do it all at once it would probably involve about 75% drain. Unfortunately it is rarely a good idea to do that and if it is especially hot you don't want to expose your plaster to the heat for too long. So you will likely have to do it in stages. You could potentially use the water to water plants and lawn, but it has to go somewhere.

You are correct, it is quite wasteful. That's why we try to nudge people away from giving their pools a constant diet of stabilized chlorine. Why the pool stores continue to do so, especially in areas where seasons are long and water replacement is low, I can't say...
 
Thank you.

What is the best way to drain the water off to water lawns and the sort and then to drain into the sewer if needed.
I was thinking maybe I could do it in 15% or 25% stages.

But I have no idea how to even drain the pool. Is this controlled via the pump ?
 
Keep in mind that if you do a little bit of the water exchange at a time, you will use far more water than if you do a 50% or more drain at once.

For small amounts, some systems have a hose bib after the pump. You can use that. Or you can purchase a sub pump from Harbor Freight or rent one from Home Depot. You would need a hose that goes to your sewer cleanout or to the street (check with your local waste water organization on how they require you to manage draining a pool).

Real bummer. This what happens with constant use of stabilized chlorine in the west were we do not drain the pool for winter nor get large amounts of rain year round.

Take care.
 

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In reality your FC may be too low for your CYA. You do not know what your CYA is, except really high.

A pool is safe to swim in when
The FC is below shock level.
The pH is between 7.2 and 7.8
AND you can see the bottom of the deep end of the pool.

Take care.
 
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