Cartridge filter with trichlor

fellowship

New member
May 30, 2008
4
#1
I was curious if someone could explain if a cartridge type filter is not a good match with use of trichlor 3in tabs in a floater as it pertains to cya levels getting high over time.

I plan to use the pool one season at a time and drain the pool at the end of the warm weather.

If I have a bucket of 3 in trichlor I would like to be able to use this season am I am risking troulble with rising cya over time with a cartridge filter?

I would like to understand this issue..

Thank you in advance
 
G

Guest

#2
A cartridge filter is not backwashed to clean like a sand or DE filter.. Backwashing removes some water from the pool which is then replaced with fill water so the CYA does get a bit of dilution with a sand or DE filter. For ever 1 ppm FC that trichlor adds it also add .6 ppm CYA. It is the nature of the chemical beast! :shock: Most pools lose about 1-2 ppm FC every day from sunlight when they are properly stabilized so that means you will have 6-12 ppm rise in CYA every 10 days. If you start with 0 ppm CYA (NOT a good idea since your chlorine will not hold in sunlight for more than about an hour) then it means that in 2 months time it is very possible that your pool will be overstabilized. If you add CYA at the beginning to help protect the chlorine from day 1 (which is what is recommended) then this time window is even smaller. What usually ends up happening is that the stabilizer levels reach 'critical mass' in the heat of summer and the pool starts having problems ranging from being cloudy to full algae outbreaks or persistent mustard algae.
 
G

Guest

#4
No, use them until the CYA is about 50 ppm then switch to bleach or liquid chlorine! You DO have a good testkit, don't you? It is probably the MOST IMPORTANT piece of pool equipment you can own. I would recommend ether a TF100 (see the link in my sig for TFTESTKTS) or a Taylor K-2006. Both use the FAS-DPD method of chlorine testing and also test pH, total alkalinity, calcium hardness, and CYA. The TF100 comes with larger bottles of reagent so you can do more tests and it has a lower list price.
 

fellowship

New member
May 30, 2008
4
#5
I have "hth branded" manufactured by taylor 6 way test kit with chlorine up to 5 ppm, pH test, total alkalinity, and a cya test which I need more reagent for.

I just don't want my cya to get out of hand. I am not sure I read my test for cya correctly.. I am looking at the black dot and as I fill the tube with more test water with reagent it gets harder to see. But it does not seem like an exact threshold where it is seen to when exactly it is not seen.

Do you know what I mean by that??
 
G

Guest

#6
It means that your cya is below 20 ppmm right now. it's an ok kit for the price but not the best out there.
 

akelley

Active member
May 17, 2008
36
#7
I also have a question about CYA. I have been using the TF kit for about two weeks now and I cannot determine the actual about of CYA I have in my pool. That is, every time I do the test I fill the entire cylinder up with the solution and can still see the black dot clearly. Does that mean I have very little CYA in my water? What strikes me as strange is the fact that I have a floating dispenser in my pool with 3 inch trichlor tablets and an offline feeder feeding the same trichlor tablets, set to max. I would think by now I should be seeing the CYA level go up? I'm also using bleach as well, but wanted to use up the tablets as I already paid for them.

Is this normal (the low level of CYA), am I doing the test wrong, or both? I'm pretty sure I'm doing the test right as it's not too difficult to follow the easy to read steps.
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,879
Silver Spring, MD
#8
akelley, if you can still see the black dot when the vial is full that is a level of zero. The CYA test can read zero even when the CYA level is as high as 20, or sometimes even 30. So really all we can say is that your current CYA level is somewhere between 0 and 30. Using trichlor will raise the CYA level, but it can take weeks to get to an appropriate level.
 

frustratedpoolmom

TFP Expert
LifeTime Supporter
In The Industry
May 20, 2007
12,177
SWSuburban Chicago, IL
#9
I have a cartridge filter, and I had CYA problems. But it took about 3 years of routine mis-management to develop high CYA and resulting problems.

With an intex pool and fresh fill water every season, chances are small that you will develop a problem...

Follow Waterbears recommendation, use your tabs and if you see your CYA getting too high, switch to bleach, consider a partial re-fill...

A good test kit-essential!!!
 

IkeRay

Well-known member
May 20, 2007
154
Houston, Tx
#10
an alternative to trichlor, if you are addicted to pucks, is cal-hypo tabs. instead of adding CYA they add CH, but with a window of 250-450 acceptable CH its more forgiving than the 30-50 CYA window. Bleach is ideal, but some people are addicted to tabs/pucks.
 
G
#11
IkeRay said:
an alternative to trichlor, if you are addicted to pucks, is cal-hypo tabs. instead of adding CYA they add CH, but with a window of 250-450 acceptable CH its more forgiving than the 30-50 CYA window. Bleach is ideal, but some people are addicted to tabs/pucks.
Bew aware that cal hypo tablets and capsules CANNOT be used in a feeder or a floater! To do so could lead to an explosion since they generate a lot of heat and pressure as they dissolve (unless it is a specially designed cal hypo feeder that has NEVER had trichlor in it).
 

akelley

Active member
May 17, 2008
36
#12
Jason, thanks for the info. I'm going to continue to use the pucks until they're gone or my CYA readings become an issue.

Adam
 

IkeRay

Well-known member
May 20, 2007
154
Houston, Tx
#13
waterbear said:
Be aware that cal hypo tablets and capsules CANNOT be used in a feeder or a floater! To do so could lead to an explosion since they generate a lot of heat and pressure as they dissolve (unless it is a specially designed cal hypo feeder that has NEVER had trichlor in it).
this I didn't know. I threw them into a new floater when I went on vacation (brand new had just bought the floater) and only had one in there at a time (had my brother taking care of my pool). reason I used the tabs was because he didn't know what days he would be there, and the tabs lasted for at least 2 days each.

/hijack :)