Green Pool (Was black at first)

[like2ct]

Hi,

Just opened my 30k gallon pool a week ago.

Some background info:

Pool has a sand filter and sand was replaced last year.
Pool is around heavy tree coverage and due to early snowfall last winter (MN) it was well covered with oak leafs which were removed in spring when the snow finally disappeared.
When cover was removed water was black. But I am sure it was the main reason for the black pool water as the year before it was clear with some debris on the bottom of the pool.


I used around 5 gallons of liquid bleach to shock and after a couple of days of filtering and back washing pool is now green (can hardly see bottom in shallow end) but it seems to be better than before.

My numbers for 5/29 were (Done with LaMotta Color Q):
FC 1.92
PH 7.1
TA 163
CH 190
CYA 9

Added that day 8.5 lbs of Soda Ash to increase PH.

My numbers for 5/30 are:

FC 2.46
PH 7.3
TA 209
CH 185
CYA 2

Now I think (here I could use advise), to add more Soda Ash, 5.5lbs to continue to increase PH.
And do another round of liquid bleach (could use advise here on quantity).

My phone app (Pool Pal) which I am using, also recommends to add 159 fl.oz or 9.5lbs of dry stabilizer.

I have been brushing on a daily basis. A small kleen cleaner robot is cleaning but the hoover bag seems to get lined with algea which contains the water in the bag when removed from pool.
It looks like the sand filter is working over time and I am not sure if it's performing right as the skimmer baskets show minimal action.
When pool is set to circulate by passing the filter the skimmers work fine. I am planning to pull the filter apart to make sure it not a clumpy mess.

Thanks,
Ernst

[PoolDoc]

1. Algae is either dead, dying, or growing. Green algae is growing. Add 5 gallons of bleach EACH evening till the algae is ALL gone / brown. Brush the pool after each addition.

2. Meanwhile, read http://pool9.net/alk-step/ . Assuming that the ColorQ is accurate -- and I can't really assume that -- you need to lower your TA. Aerate to do so; your pH will rise. How much lower depends on whether you have a vinyl or concrete pool. Do not add any more soda ash.

3. Your CYA is too low, but it would be better to raise it AFTER the algae is dead. A good way to do so is use dichlor, which adds 9 ppm of CYA for every 10 ppm of chlorine added. See http://pool9.net/sams-dichlor50/

4. Do not add any other chemicals till the algae is dead, the pool is clean, and the TA is more reasonable.

5. We have plenty of evidence that electronic readers are generally very inaccurate and untrustworthy. However, I did some checking on the ColorQ Pro and would acknowledge it's better than most . . . but it's very sensitive to temperatures and wait periods (covered in the instructions). If you do not observe those requirements, you can get very inaccurate results. If you do follow the instructions, the chlorine test up to 5 ppm, the pH, test and the TA test are probably as accurate as the K2006. The calcium test has problems, and the stabilizer test is apparently erratic. The most comprehensive discussion I could find is here:
http://www.poolgeniusnetwork.com/for...photometer-are

6. You need to get a cheap OTO/phenol red kit, since you can't test chlorine accurately above 5 ppm with the ColorQ, and above 10 ppm, the sample may bleach out and read low or even zero.

[like2ct]

Thanks Doc,

This am I did add unfortunately already additional Soda Ash (5.5lbs) to increase the PH.
My readings in the late afternoon are (I will verify my future ColorQ readings with my OTO test kit):

Pool has vinyl Liner:

My 5/31 (6 hours after soda ash addition)

FC 1.99
PH 7.6
TA 249
CH 189
CYA 3
Total Chlorine 5.27

Just Added this evening 5 Gallons of Liquid Chlorine, brushed and will repeat as instructed (and hope to see dead algae soon). Will do some reading on the other points.

Thanks for the advise.

Ernst

[PoolDoc]

FC 1.99
PH 7.6
TA 249
CH 189
CYA 3

The ColorQ is MUCH more accurate than an OTO kit; it's just not reliable at chlorine levels above 5 ppm. I'd still encourage you to get a K2006; they keep a long time, and even if you mostly use the ColorQ, there will be times when you need an accurate CYA or CH reading, or when the chlorine is above 10 ppm.

[like2ct]

Pool still green, doing the daily 5 gallon liquid chlorine/brush job.

Just had 5" of rain and lot of tree crap in the pool.

Numbers for today (I have the K2006 kit on order).

6/2

FC 3.86
PH 7.4
TA 227
CH 186
CYA 9

Looking now for ways to prepare for aeration (considering making a PVC pipe aeration attachment for one or two of the return lines).

Have pump set to circulate and slide is running as I understand my PH is still too high to do a full blown aeration.

[PoolDoc]

You don't have to do aeration fast -- it will take place slowly if you do nothing but maintain a lower pH. So, go ahead and lower the pH. If you can, adjust the pool returns to 'riffle' the water.

Worry about getting the chlorine up, and killing the algae. If it's still green with 5 gallon doses in the PM, go to 10 gallon doses! You'll spend less, killing it quickly than by slowly beating it to death.