Just opened pool, Need to raise pH, poolMath is suggesting 80 lbs of borax...

[billyz]

Just looking for a little advice. I've just opened my pool (first time pool owner). Test results are below in full. I'm balancing and converting to SW.

I just opened the pool. It was winterized by the previous owner of the house so I'm inheriting his chemistry and leaves... When i uncovered the pool, the water was clear but the bottom was full of leaves. I worked all day yesterday and removed all the leaves, shocked the pool with some "hth shock and swim" he had left behind, and added a couple chlorine tablets he also left. My plan is to get the water close to balance while adding the salt for the SWG, then just stop adding chlorine and turn on the SWG.

This morning, the water is very clear (Hooray!) but the chemistry needs some adjustment. My pH is off-scale on the low side so I'm having trouble getting a good idea of how much borax to add without cranking up the Alk. PoolMath suggests 80 pounds of borax assuming a starting pH of 4 (which i have no idea if that's correct). I think my biggest question is, how much boarx should I add at first, and how long to wait before retesting to see where the pH has landed after an incremental adjustment?

Here are today's tests (gray lines are just the difference from result to target from my google sheets doc for tracking)

Date	pH	7.2	FC	4	CC	0	TC	4	Ch	400	CYA	75	TA
5/29/2016	4	-3.2	7.5	3.5	0	0	7.5	3.5	250	-150	60	-15	20

 

[Richard320]

Where did you get a pH reading of 4?

If it's a digital tester, pH is probably beyond the range of it and the readings will be all wrong.

If your TA is really 20, start by raising that to at least 50. Otherwise pH adjustments will be wild swings if you overshoot just a little bit. Give that some time to mix, half an hour or so, and brush a little, and then recheck pH and TA. Plug your new values into poolmath. If the pH is lower than 6.8, use 6.8 as now and 7.4 as target and add Borax accordingly. Another half hour with some brushing to ensure it's well-mixed, and test pH again. Same thing. 6.8 now, 7.4 target. Dose. Mix. Retest. Repeat until the pH comes into the 6.8-8.0 range and recheck TA as well and the last adjustment should nail it.

 

[billyz]

Where did you get a pH reading of 4?

That was just an estimate since nothing seemed to test lower than 6 (previous owner left a bunch of test strips i used just to see if the pH was as low on those as my TFT kit in case i had bad chems). A 0 in PoolMath resulted in a call for a couple hundred pounds of borax... i decided that wasn't possible.

I'll toss some baking soda in for the TA (according to poolmath) and I've got the return jet breaking the surface for a slow climb on pH while the TA comes up as well. I'll re-test in a couple hours and see where it gets me. Thanks for the advice.

Is it safe to assume that too low of a pH would make the water uncomfortable to swim in, or is the water in a safe range, just still needs balancing?

 

[Richard320]

That was just an estimate since nothing seemed to test lower than 6 (previous owner left a bunch of test strips i used just to see if the pH was as low on those as my TFT kit in case i had bad chems). A 0 in PoolMath resulted in a call for a couple hundred pounds of borax... i decided that wasn't possible.

I'll toss some baking soda in for the TA (according to poolmath) and I've got the return jet breaking the surface for a slow climb on pH while the TA comes up as well. I'll re-test in a couple hours and see where it gets me. Thanks for the advice.

Is it safe to assume that too low of a pH would make the water uncomfortable to swim in, or is the water in a safe range, just still needs balancing?

It will probably leave people with dry itchy skin and burning eyes. 7.2 to 7.8 is the comfort zone. And extremely acidic water can also dissolve plaster surfaces and the metal innards of pool pumps and --especially expensive -- heaters. Check out the pictures in this thread: Maintain your chemicals correctly

 

[billyz]

Thanks, that's what I figured but had to ask. The whole family is itching to get into the pool.

I dumped most of a bag of baking soda in a little over an hour ago, just letting things mix a bit. Tested the pH and FC when i dumped it in, FC was still over 5 and pH still below 6.8. Will probably test again in about another hour.

Thanks again

 

[duraleigh]

Pump running, you will register most changes in 30 minutes. It's going to take more than a bag of baking soda. Dose and then test.

 

[billyz]

Things seem headed in the right direction. pH is almost there already and I may have overshot the TA. Going to be leaving everything else alone and going to re-test again after dinner. This is my first day with the test kits. As easy as they are, i'm sure there's some fluctuation here from human error...

Date	pH	7.2	FC	4	CC	0	TC	4	Ch	200	TA	75	CYA	75
5/29/2016 11:00:00	<6	??	7.5	3.5	0	0	7.5	3.5	250	50	20	-55	60	-15
5/29/2016 16:00:00	7.2	0	7.5	3.5	0	0	7.5	3.5	250	50	120	45	80	5

is it unusual for the FC to have stayed in the same place with no new chlorine being added? The SWG isn't on yet and there are no chlorine tablets in.

 

[AimeeH]

I would say that isn't unusual seeing your cya is 80? Now. Especially with no bathers. Was sun on the pool? That would bring down your FC a bit.

 

[billyz]

Yesterday was a partly-cloudy kind of day. Today there is much more sun and FC is down to 5 from overnight. The pool is already in full sun. I'm planning on letting the FC fall until it's closer to 2-3 before turning on the SWG (salt is already in).

pH is still holding at 7.2. I'm thinking of adding in a little bit more pH booster to bring it closer to 7.4-7.5.

The CYA test, as the insert even states, is really subjective. I feel like i could test the same sample of water 3 times and get 3 different results. Any tips on getting consistent results with that CYA test?

now if i could just get my heater to turn on i feel like i could be swimming today...

 

[AimeeH]

Yes, that CYA test is subjective. Make sure you're doing it in full sun with your back to the sun.

With CYA of 80, I wouldn't let my chlorine drop below about 6. See the chlorine/CYA chart.

Pool School - Chlorine / CYA Chart

 

[billyz]

Thanks for the chart. I'll keep my sights on FC 6 for now, since that's an OK level, just higher than I would prefer. I'll look to getting the CYA down, but I should probably work on consistent results from the CYA test before I start playing with water chemistry to adjust it.


If I do need to lower it, from some initial research it looks like a partial drain and refill is the only real way to lower CYA. Is that correct?

 

[AimeeH]

Yes. Pretty much......a drain is your option.

And saying 6 is a little higher than you like it is indicative that you haven't read up on the chlorine/cya ratios. Check out the information on that page I linked previously. If you go below 6 with a CYA of 80, you no longer have enough to chlorine to sanitize your pool from even normal bacterial contaminants let alone sending an invitation for an algae party.

 

[Richard320]

Thanks for the chart. I'll keep my sights on FC 6 for now, since that's an OK level, just higher than I would prefer. I'll look to getting the CYA down, but I should probably work on consistent results from the CYA test before I start playing with water chemistry to adjust it.


If I do need to lower it, from some initial research it looks like a partial drain and refill is the only real way to lower CYA. Is that correct?

Yes. Reverse Osmosis is unavailable in most of the country, and the BioActive CYA reducer hasn't been very successful from reports here, so draining and refilling is the fastest most economical way to do it.

Check your water company website for information. If you have tiered rates, they might waive them every so many years to allow swimming pool refilling. Or if they add sewer fees based on water use, they'll waive them for pool filling. It costs nothing to check. Search for swimming pool on their website and see what it says.

 

[billyz]

Aimee - thanks again. I did actually read up on the relationship between FC/CYA from that link. Wanting to operate at a lower FC is why i was asking about lowering the CYA. I understand that to have a lower FC i first need to have a lower CYA. Also, thank you for the tip on the CYA test. I think i've finally figured out how to get consistent results. Holding the tube at the top rather than the bottom helped me a great deal. With that improvement i'm just about right in the middle between 60-70, so i'm going to go with 70 to be on the safe side and aim for 5FC.

Richard, thanks for the tip on the water company! I'll be looking into that, as you said, it doesn't cost anything to ask.