In SLAM I trust...

[Poolguy99]

I decided this year that I would give the SLAM methodology a try when opening my pool instead of spending hundreds of dollars on different chemicals 'recommended' by my local pool store.

When I pulled the cover, I could see bottom even though it was green. My initial levels were CYA 0, Alk 110, pH7.2 and FC 0. I got the pH up to where it needed to be then started dumping 12.5% liquid chlorine into the pool.

I couldn't get the chlorine in there fast enough before it would be converted to CC and my FC would plummet. After giving it a few days, I added liquid stabilizer to get the CYA up to 30, the CC started going down, the FC started going up and the water started the typical transformation of going from green to clear.

Fast forward a week, and all of the green was gone but the pool was cloudy white. I vacuumed to waste and used my new Hayward m500 a few times as well as scrubbing it down a couple of times a day but it remained cloudy.

While at the local pool store, I grabbed a bottle of floc just in case but I decided to ride out the SLAM process and just threw the floc on the shelf. This morning I went out, about 9 days after opening the pool, and I could clearly see the bottom and it was crystal clear!

I'm losing about 1ppm of FC each night but I'm losing about 6ppm during the days because of the sun. My new levels are:
FC 12
CC 0.5
CYA 30
ALK 110
pH 7.4

I'm thinking of adding another gallon of liquid stabilizer to bring the CYA up to 40 to help the FC deal with the sun. I'm planning to add a pump to inject liquid chlorine on a nightly basis to avoid the pucks and having to manually dump a couple of gallons in each night.

I just wanted to thank the team for coming up with the SLAM process! It produced incredible results at a fraction of what the local pool store was offering to charge.

 

[Catanzaro]

I'm losing about 1ppm of FC each night but I'm losing about 6ppm during the days because of the sun.

A 6 ppm loss during the day is still excessive. You are not done with your SLAM, even though you tested a 1 ppm loss overnight. The question is what kit are you using to test your water? My pool, without any activity will consume about 1 ppm daily, registering 0 cc. It is highly recommended you continue your SLAM. Also, the higher the amount of TC you have in your pool, the more you will loose daily. It is a %, not an flat amount (like 1 ppm daily). Each week, with very little activity, I was about 1.33 and when there is a lot of activity during a day, I could be at 4 ppm extra loss (but we are talking 15 people with heavy oils, hairspray, etc).

Brush your pool walls real well as algae could be hiding. Unless your CYA is actually lower. Please advise how you are testing your water and how old the reagents are? Thanks!

 

[Poolguy99]

I'm continuing the SLAM and making sure to keep the FC elevated at the appropriate level. I've been brushing my walls a couple of times a day but don't see anything anywhere at this point.

I picked up the K-2006C at the beginning of the season and have found it to be invaluable. I checked the reagents date and they're less than a year old.

I did the CYA test and it came out to be at the 30 level when the dot 'vanished'. That's why I was wondering if I should raise it to 40 to help with the sun (my pool sits in the sun all day).

 

[proavia]

If you have lights, ladders, etc. you may want to pop those out and clean them too. Algae can hide in them and also around the skimmer weir door.

I notice you have a IG concrete pool. Is it plaster or does it have a liner? If no liner, do the CH test too.

When you get ready to add stabilizer, I'd suggest the granules. Much more cost effective than the liquid. Hang it in socks in front of a running return - a few hours later, knead the sock for about 10 minutes to dissolve the stabilizer into the pool water. About 24 hours later you can do the CYA test again to see what the new level is.

 

[Catanzaro]

I am betting the CYA reading is slightly off and the test is subjective and hard. Maybe you are lower than 30, and yes increase to 40-50 and work from there. In the first few years, I always started at 50 and allowed to drift down to about 30 by season end, bumping back to 50 before closing and opening to about 30 and running the same cycle. Keep us posted and this is probably the reasoning behind chlorine loss.

 

[jblizzle]

With a CYA of only 30 PPM, it is not unreasonable for you to lose 50% of your FC to the Sun every day

 

[Poolguy99]

I tested CH this morning and it was 250 so that should be ok.

I added another gallon of liquid stabilizer and will take a reading tomorrow morning to make sure the CYA raised up by about 9 (per the calculator) then I'll watch what happens to FC during the day.

 

[Catanzaro]

Wait at least 3 days before testing CYA. Assume that you have enough and see how much chlorine loss occurs during the day. I would test in the morning (7 a.m.) and at night (9 p.m. or 10 p.m.). If you test in the a.m. and you add chlorine, I would suggest allowing to mix for at least one hours, if not at night after testing with the filter running.