Questions before I SLAM

[gwtw]

I finally got my Taylor K-2006 test so I should be ready to SLAM tomorrow when it finally stops raining and I'll be home to monitor things. I just have a few questions before I start this.

1. Right now, my test shows that my PH is 7.6. Do I need to lower it, and if so, how do I do this?
2. Do I need to be concerned about my Alkalinity or Calcium Hardness levels before I slam? (I didn't test my Alkalinity or Calcium Hardness levels yet since I don't want to waste any of the solution, but the pool store that uses a Taylor test has told me multiple times that my calcium hardless level is very low at 100 and my total alkalinity was 80 once, and 100 the second time I had it tested.
3. My water is clear now (after adding a gallon of bleach each night for 5 nights) but there is some yellow dirt at the bottom of the pool and around my light that may be mustard algae. If I vacuum to waste to get rid of this, could my CYA level lower? If I did the CYA test correctly, it is showing that my CYA is at 30 now, so I don't want to do anything that could potentially lower it, if I can help it. Could I start the SLAM process without vacuuming first since there isn't an abundance of yellow algae or dirt in the bottom of the pool currently or will the SLAM process go quicker if I vacuum it up first?
4. Since getting my CYA up to 30, I'm able to keep chlorine in my pool now but it still drops some during the day. Tuesday night, I added a gallon of bleach, which should have gotten my level up to 8, but my level was only 3 at the end of the day yesterday. Is this normal, or is there a chance that my CYA isn't 30 after all? That CYA test is very hard to interpret, so I'm not 100 percent certain that the CYA is actually 30. If it would help, I could add a pound of Dichlor tonight to increase my CYA a little bit more.

I'm sorry to ask so many questions. I'm new to this so I want to make sure I'm doing everything correctly so the SLAM process will go as quickly as possible. I really appreciate all of the advice everyone has given me so far.

 

[matimer]

Yes I would lower the PH down to 7.2. Once you start the SLAM process your PH will be inaccurate. Also, I've done the SLAM a few times for mustard algae, and if I have the PH at 7.6 it takes a lot longer for the algae to disappear.

As far as your CYA the chart shows 30 to be okay. If anything, I use liquid chlorine to raise the chlorine to mustard shock level and a few tabs to stabilize the chlorine while I'm at work. Like you describe my chlorine can go from 8PPM to 3PPM in this 100 degree weather. During SLAM my chlorine went from 24PPM to like 16PPM. With one tab it stayed at 20-22PPM.

One thing about mustard algae is don't give up. I didn't see significant results until the 3rd day. You must not stop until you have removed 100% of it. It took me more than a week to get it under control.

 

[gwtw]

Do I need to vacuum up the mustard algae before starting the SLAM? As I said before, I really don't want to vacuum to waste if it might lower my CYA level and I'm concerned that if I just vacuum normally that this stuff might clog my filter. I also don't understand how I will know if the mustard algae is gone if I vacuum it all up before I start this process since my water is already clear. If I don't vacuum before starting this, will the mustard algae just disappear? Do I need to backwash anyway before starting this process since my guage on my filter currently shows that it is 4 above the normal level?

 

[_shorty_]

That's probably up to you - the more stuff you can physically remove, the less overall chlorine you'll use and the less time your SLAM should take (in theory). I'd probably choose to brush and vacuum well, backwash, then start my SLAM. I'm a noob though - so take that advice for what it's worth.

 

[matimer]

When I had mustard algae I didn't vacuum until I was done with the SLAM process. Ideally you should beforehand , but it didn't make a difference in my scenario - mustard algae would appear the next day. If it looks clean and clear and the only issue you have is mustard algae I would skip it.

 

[Agent99]

I would say you *probably* want to dial in your pool to better numbers. pH is the only one you CAN'T do while SLAM'ing but it is within range so I wouldn't worry about it but one poster thought he got better results with more neutral water for eliminating the algae. Up to you.
While you are SLAM'ing, I think you could increase your CH but you have a fiberglass pool so I don't recall what good numbers are for that style so check on that. I have plaster and CH is 200-400.

Personally, I would remove as much organic content from the pool as possible so more chlorine is available to get stuff you can't easily get out. Yes, it'll lower your CYA some but you can dump in some dichlor as you suggested. It'll bump up your FC and CYA (10:9 ratio of FC:CYA). CYA isn't an exact measurement anyway. Keep it 30-50 range and you should be okay.