SWG and slime buildup?

[canadianpaco]

We have an inground salt water pool. The SWG is set at 40%, chlorine is reading 1ppm and the water is clear. ph 7.4.
Our problem however is that there is a slime build up on the cartridges. Water pressure will slowly decrease and we have to take the cartridges out to power hose them clean.
Our pool co. recommended that we shock the pool (40l liquid chlorine) and use an aligicide. Then soak all the toys, equipment in the pool, brush down the walls, etc.
Three days later, the pressure is rising which means the slime is back.
Any advice would be appreciated.

 

[Bama Rambler]

Post a full set of test results and how you got them.
pH
FC
CC
TA
CH
CYA

You most likely need to shock. Real shock not pool store shock.
Post the results and we'll help you get rid of this.

 

[canadianpaco]

pH=7.5
FC= 1ppm
CC= don't know
TA= 140
CH= don't know
CYA= don't know

From the sounds of it, I am lacking alot of info. I guess my pool testing kit isn't complete enough for me to get these answers. So I'll take a sample to a local pool store and get the rest of the answers. Ugh...

 

[duraleigh]

Re: Salt water and slime

Merged threads and deleted double post by OP. Butterfly

Without your test results for CYA, it's a little guesswork, but the most common issue is you didn't get your chlorine high enough longenough to completely clear the pool.

Shocking is a process......not a one-time dosage.

read "How to Shock Your Pool" up in Pool School.....that will help you get a better idea of what you need to do.

Posting a full set of test results is also a very good idea.

 

[Bama Rambler]

Go ahead and get the numbers from the Pool Store and post them, but if you want to take control of your pool you need to get your own good test kit. Going by your name and you use of Litres for the volume measure I assume you're in Canada. Find someone that sells the Taylor K-2006 (not the K-2005) and buy one.

 

[canadianpaco]

That sounds like a must- I'll get a new more complete test kit for sure.
I'll also go to the "How to shock a pool" link under Pool school.

I'll keep you posted, and thanks!

 

[canadianpaco]

I'm back with results to discuss....

pH: 8.0
FC: 0.4 ppm
CC: 0.5 ppm
TA: 160ppm
CH: 190 ppm
CYA: 10 ppm

Pressure is slowly rising. If it matters, it's a 62000l in ground
Thanks in advance!!!

 

[Bama Rambler]

You need to get your pH down first. Use Pool Calc to figure out how much acid to add.
You need to do an overnight chlorine loss test but without a good test it's almost impossible to do one.
Go ahead and bring your FC up to shock level tonight.
If your CYA is to be believed you should bring it up to about 30ppm.

 

[tphaggerty]

Actually, your CYA probably needs to be between 60 and 80 ppm. CYA appears to be a crucial factor to get SWGs to work correctly. Once your CYA is at that level, you will need to have your FC at about 4 ppm.

I would look at your SWG manual (or on the inside cover of the SWG controller), the correct CYA # will be there and should be followed.

 

[Bama Rambler]

The reason I said 30 was that they need to shock and it's easier with the CYA lower. Once finished shocking they do need to bring it up to the recommended level.

 

[canadianpaco]

What is used to raise CYA?

 

[Bama Rambler]

It's stabilizer or conditioner. Look for Cyanuric Acid as the ingredient.