Trying to help a friend and FC testing was orange, what now?

[singingpond]

Headed back there tonight for another testing. The CYA was 90. There has been no chlorine added to the testing should be interesting this evening.

Tested water @ 6 p.m. and PH was slightly low @ 7.2 and FC was yellow and not orange, either 5 or over but under 10...

Once you start SLAM process, I assume you will be testing chlorine levels with FAS/DPD, not OTO chemistry.

Once CYA level is down to 50 and PH is up to 7.6...

I think you've probably seen this in further reading about SLAM, but lower pH (like the 7.2 the pool is at now) is better for chlorine effectiveness -- i.e. raising pH to 7.6 at this point would work against you a bit.

 

[Leebo]

To help you learn about the SLAM Process somewhat more, please watch this 10ish minute video. It covers the steps of the process that you'll need to know.

 

[Catanzaro]

Do I need to bring the PH up before the SLAM? I will watch the video. Luckily my pool has had no need for anything. I keep my levels @ the Target FC based on my CYA.

I did have one question about CYA. Does CYA at all decrease over time, outside removing and adding fresh water. I understand what increases CYA or it pretty much stays where it needs to be.

 

[Leebo]

The main reason why people want to decrease the pH before a SLAM is to give the pH some "wiggle room" during the SLAM. Once the FC levels are above 10, then the pH test will display false readings making it worthless. By lowering the pH level before the SLAM you can forget about it in the vast majority of cases with no issues. If your pH is at 7.2 now then I wouldn't worry about it. It will tend to increase on it's own. Forget about it for now and focus on the FC and CYA levels.


As for the CYA decreasing over time......the simple answer is sorta. They do decrease VERY slowly on their own. It's so slow however that it's best to treat it as if they didn't decrease on their own. For the most part, the ONLY way to decrease CYA in a pool is via a drain/refill as you are doing.

 

[singingpond]

Do I need to bring the PH up before the SLAM?

No. As stated, raising pH will work against you. See post #6 in this thread:
http://www.troublefreepool.com/threads/83479-Chlorine-and-pH-relationships-Chem-experts-knowledge

I did have one question about CYA. Does CYA at all decrease over time, outside removing and adding fresh water. I understand what increases CYA or it pretty much stays where it needs to be.

I remember reading in several threads on the forum that CYA typically drops by 2-3 ppm monthly (normal breakdown rate of the chemical under conditions in the pool). You could search to verify.

 

[Catanzaro]

I tested the water @ 9:30 this morning before the sun came up. Here were the test results.

CYA @ 60 (down from 90)
PH @ 7.2
TA @ 100
FC @ 2.5 with the FAS-DPD Test
CC @ 0
Did not test calcium levels.

Unfortunately it looks like the previous owner of the pool or the individual who threw in 6 lbs. (if not more) of shock with stabilizer in it bleached the liner (what a shame) but too late now.

There was a little bit of algae today so we brushed all the walls, shocked the pool (which I do not like to do but had to) and as the algae broke up. We vacuumed & brushed the pool and within 30 minutes the pool looked great. I will be testing the water again on Sunday and Monday.

Q: There was a small amount of algae on the walls and floor (very minor). Does this call for a SLAM or @ this point maintain the appropriate FC levels? My friend will have to drain a bit more water to bring the CYA level down to about 50 which is our goal before he closes the pool.

In the spring we will be ordering a new TF-100 Test kit to have him take control of his pool. At this point it is best to wait as the pool will be closed in the next week or so.

 

[Smykowski]

Visible algae is one of the signs of needing to SLAM, but if you're not in a hurry you can try maintaining slightly higher FC levels and just do a lot of scrubbing to help circulation.

Prepare yourself for it not working and needing to SLAM to get it completely clean. Better to SLAM now and close a clean pool than leave it and have to clean up a worse mess in the spring.

 

[pwrstrk]

+ 1^^^. With a small amount of algae the SLAM should go quickly.
I would get it taken care of prior to closing. ?

 

[Catanzaro]

I will tell my friend he will need to keep the levels up during the SLAM process. Thank you.