Green water in pool

[Dudek]

Initial post please bear with me. I have a 25,000 gallon in ground cement pool, there was a pool cover problem and the water was bailed out and fresh added. However some debris was left in the pool as we couldn’t leave it empty for too long and it was too slippery to walk on the slanted surfaces for removal. This debris can be vacuumed with the Hayward automatic pool vacuum and its taking quite a few filter basketfuls so far with some more to go. With murky green water we can’t see more than 3-4 feet in but it’s nice to have the automatic gizmo vacuuming the pool. It worked wonders last year.

I presently have the floater in with 3 3” tablets of what I think is dual chlor tablets, I’ll check tomorrow and get back with that into. I didn’t add Stabilizer last year as I thought the tablets in the floater had stabilizer in them and we had crystal clear pool water all season. I would shock with 2 one pound packets of HTH super sock it every 7 – 10 days depending on when the chlorine test strip showed less than 1-3 (Ideal) when no chlorine showed up and depending how heavy the swim activity was, if it was super hot out, etc.

Last year we added new water as well but all the debris had been removed first. I’m running the filter 24/7 and shock with 3 one pound HTH shock at night and in the morning the water is a cloudy light, blue color. By mid afternoon with the vacuum running in the day time it turns light green again and I figure it is because the chlorine is being consumed killing the algae.
This year should I add stabilizer and do you need stabilizer if the chlor tablets already have stabilizer in them?

[Dudek]

The tablets in the floater are HTH dual action 3” chlorinating tablets.
Trichloro-a-Triazinetraine 93.5%
Copper Sulfate Pentahydrate 1.5%
Inert Ingredients 5.0%
Total 100%
Available chlorine 84%

“protects against bacteria and algae”
“Sun protected for extended chlorine life”

Does the last sentence mean there is Stabilizer in the tablets? The reason I'm asking is that if there is Stabilizer already in the tablets would that boost the Stabilizer level if I added separate Stabilizer?

Last year it ran all season with no added Stabilizer, just tablets and shock, which is confusing as other sources say I must add Stabilizer to fresh water.

I noticed that since registering I've lost access to 95% of the useful information here. I understand the need to guard against spammers, etc. but you must also understand that I do not give out personal information to protect my personal privacy, guard against identity theft, and above all remain anonymous.

Does the new user blocking situation last very long? In the meanwhile I can live with the inconvenience and not login when I browse. I'm going to call the HTH Help Line and see what they have to say.

[Watermom]

You don't want to use those tabs. They do have stabilizer in them, but they also have copper. You do NOT want copper in your pool. Contrary to popular belief, it is not chlorine that stains pool surfaces, fingernails and hair green; it is the copper!

We really need some good testing numbers to be able to advise you. If you don't have a good test kit, that would be the first order of business. We suggest the Taylor K-2006 or 2006C which you can get through the link in my signature below. (It won't be available locally.)

Once your registration is completed, you will have access to the whole forum. Hopefully, it will be done soon. It takes time and there are lots of new members registering right now as they are trying to get their pools up and running this year.

Welcome to the Pool Forum!

[BigDave]

... I understand the need to guard against spammers, etc. but you must also understand that I do not give out personal information to protect my personal privacy, guard against identity theft, and above all remain anonymous.

Does the new user blocking situation last very long? ...

It is unlikely that you'll get wider forum access while hiding your identity from the PoolForum Admin.

[PoolDoc]

membership updated to "general" (moderated) status.

Basically, I trust you about as much as you trust me.

I'm reminded every single morning -- when I have to clean up all the bogus registrations -- that anonymity is not only for those who want to remain private, but more importantly (for me) is the refuge of spammers and hackers.

[Dudek]

membership updated to "general" (moderated) status.

Basically, I trust you about as much as you trust me.

Thanks. “Trust but verify”. The water has just cleared up and I can read a dime heads or tails in the deep end. So far free chlorine and total chlorine have been good in the morning and zero by the end of the day. I don’t have a CYA test so I took a water sample to a pool store and they said my CYA was 30 and all other levels matched the readings I got which were all good, Ph on the high side 7.8 – 8 which again exactly matched the readings I got with my test strips. This recently elevated Ph elevated could be because of rains we’ve recently had (it was 7.2 – 7.6 up until before the recent rain) and accumulative effect of the recent daily super chlorination (shocking) in the evenings.

I’m assuming the daily chlorine consumption is due to the heavy algae problem that just got cleared up and low CYA. Pool store recommended a 4 pound tub of CYA and I added ~ 3 lbs. The instructions said not to backwash for 72 hours so I am assuming that it takes roughly 72 hours for this particular formulation to fully dissolve.

Last year I had clear water and maintained free chlorine and total chlorine at a consistent 1-3 using 3 chlortabs in the floater and shocking the pool with 2 lbs of HTH (60% available chlorine) every 7-10 days, which was when then chlorine levels would drop to zero. The chlortabs would last about a week or so before needing to be added again depending on heat, swimmers, etc. I did not add CYA last year but we didn’t have an algae problem either. The worst it got was a slight milky color once or twice that cleared up overnight by shocking the pool and running the filter constantly up from the normal 12 hours per day on timer – 2 hours on, 2 hours off. I tested all last year with test strips.

I will likely discover this on my own but will the need to super chlorinate every evening to bring the free chlorine and total chlorine back up from zero to the ideal 1-3 range taper off? I’m hoping the increased CYA will slow down the chlorine consumption and bring it back to last year’s consumption rate.

I wasn’t able to test this evening and I did not super chlorinate. I’ll be using my last test strip tomorrow morning and in part the pool store visit was also to verify that my test strip readings were actually on the mark according to their water testing equipment. I just had my first day of clear water this season so I’m happy about that.

[PoolDoc]

We push the K2006 very, very hard for several reasons:

1. Pool store test are usually rather inaccurate, and strip based tests for CYA are horribly inaccurate. You cannot run your pool successfully over the long term without knowing what your CYA levels are. Remember, pool stores make MORE money, if your pool stays screwed up, so they have ZERO incentive to use more accurate, but more expensive test methods!

2. As CYA levels rise, you need chlorine levels to rise in compensation. (The Best Guess page, linked in my signature explains). The ONLY way to do this is use OTO (yellow drops) at ranges NOT shown on the test kit, OR to use the DPD-FAS testing Taylor developed, which is found in the K2006. Pool stores do NOT sell kits with DPD-FAS test methods.

So . . . get a K2006 and use it. Trying to answer the questions you have posted above, without the chlorine and CYA info, is a bit of a waste of time on both our parts. To some degree, what you've posted is just an example of what we've always taught: if you can get your water half-way right and KEEP it there, a month of normal care is much, much easier than even a single brief algae episode.