Rising pool pH with SWCG

[PoolDoc]

Hold the horses!

If your spa "is 1 of 5 Caretaker returns", then the water for the spa and the pool is mingled, and you have to treat BOTH, as one unit.

Let's take a step back.

1. Order a K2006 or K2006C kit, and let's find out what's really in your pool. (Links for Amazon purchase in my signature -- do NOT confuse K2006 with K2005!)

2. Take, and send, pictures of the pool, spa, piping, heater, & valving to [email protected] with the subject, "PF thread #14386" and I'll post them. (That link will expire, by the way. It will be good for at least a week, however.)

3. Then, after we understand what's in your water, and how your pool and spa are connected, we can make better recommendations. That goes for high pH too. Without knowing what sort of equipment you have, and what your alkalinity and calcium levels are, we can't make good recommendations there.

[spibill]

Ordered kits today. Will work on pictures. Thanks

[PoolDoc]

Hi Bill;

Waterbear, one of the most experienced posters here, took the time to write up a detailed alternative approach to using borax for you. However, his post included a couple of points of chemistry I'm not sure about, and more significantly, an operational recommendation that I've avoided in the past.

It sounds like you've handled muriatic acid enough to know about the fumes -- they are not nice, and can be both rather dangerous and quite frightening to pool owners. Anything that increases the exposure of the acid to the air -- such as pouring the acid into a measuring container -- dramatically increases the quantity of HCl gas (the fumes are actually the acid, itself, which is otherwise dissolved in water) present in the atmosphere. For this reason, it's been my policy, and one I've encouraged my moderators to follow as well, to avoid ANY instructions that required pool owners to attempt to measure acid quantities exactly, since this normally means pouring into a measuring cup.

The moderators and I have discussed this, but I think we need to have a discussion among the larger group of contributors to the site, a group in which Waterbear is certainly a leader, and come to a consensus we can operate by for the safety and comfort of PoolForum uses generally. So, I moved Waterbear's post to the China Shop, since the follow-up discussion is likely to get rather detailed, and to NOT be focused on your particular issues.

You can read Waterbear's post here:

http://www.poolforum.com/pf2/showthread.php?14387

and my guide to applying muriatic is here:

http://www.poolforum.com/pf2/showthread.php?13111

Hope all works well for you.

[spibill]

I hope you got the pictures. Test kit is due early next week. Want to make sure you noticed I have an UltraPure Uv Ozone generator also. Didn't know this and had no information from builder, but went online to get product info. It's a UPP25, good for up to 25,000g pools, generating 0.146 gm/hr. Seems a bit of an overkill, but will reduce chlorine need and extend the life of the SWCG. Currently have IntelliChlor at only 20% on. Don't think UltraPure would be part of why the PH rises from what I've read. Thinking my pool just runs at higher PH w/o any borax. I have all of he materials, borax & acid, but am waiting for the test kit before I do anything. From test strips, it looks like I have NO CYA and TA is 100 to 120. If I understand the info from the Forum, may need to lower TA before I add borax. I think that will be easy since I have the jets in the spa and can have the spa water flow into the pool while running the jets.

[PoolDoc]

Here are your photos:

Pool:


Equipment


Controller & Ozonator


Caretaker layout


Caretaker pump requirements


Original design

[PoolDoc]

It might be best to wait till you have the kit, and can test systematically, before deciding what your pool's normal pH trend is.

Plus, there are several facts you need to consider:

+ It's not really possible to maintain BOTH a 'normal' pH AND 'normal' carbonate alkalinity levels, on a jetted spa or pool. The reason is that, at pH levels in the 'normal' range (7.2 - 7.8) aeration will ALWAYS strip carbonate alkalinity, until the pH goes up above 8.0.

+ Depending on the volume of AIR flow, a UV ozonator will tend to provide a CONSTANT source of aeration on your pool.

I'm actually discussing this issue with some of the moderators and contributors, and how we should respond. Historically, I've tended to encourage folks with spas to go elsewhere. For one thing, I personally don't like spas. But, more importantly, I don't have 'SpaSolutions" that parallel my 'PoolSolutions'.

One problem is the whole pH / can't maintain carbonate alkalinity just mentioned.

The other is, that stand-alone spas tend to be cess-pools. You can take care of a pool pretty easily with once-per-day attention. But the methods that work with a pool will not work with a spa, because the people to water ratio, and thus, people goo to total residual chlorine ratio, is so much worse on spa.

It's possible that the ozone system is a good idea for you, precisely because it will NOT create a sanitizer residual. Constant ozone feed will not create high levels of ozone, like constant chlorine feed would do.

But, I really don't have a good answer on the pH.

I can't tell you to forget about the alkalinity -- which I would do if you had anything OTHER than a concrete pool & spa -- because super low alkalinity may well result in plaster damage. But, there's simply no way to maintain 'normal' pH and at the same time 'normal' carbonate alkalinity, on a highly aerated pool & spa.

Here's what I suggest:
1. Get the K2006, and let's get a couple of weeks of chlorine + pH + TA readings under your belt. You'll also need CYA and calcium readings, but those don't need to be repeated. (There are only 6 CYA tests in the kit -- so don't waste them!)

2. Let me pursue this discussion with Chem_Geek and others, and see what we come up with.

3. Take a look at this page on PoolSolutions:
http://www.poolsolutions.com/gd/hiphpool.html
It's very relevant to your situation, as is this one:
http://www.poolsolutions.com/gd/lowe...p-by-step.html

4. Then, let's take a look. It may be best to run your pool & span with very low CA, low calcium and high pH.

[waterbear]

carbonate[/I] alkalinity levels, on a jetted spa or pool. The reason is that, at pH levels in the 'normal' range (7.2 - 7.8) aeration will ALWAYS strip carbonate alkalinity, until the pH goes up above 8.0.

Ben, I have to disagree with you. I have a similar setup as the OP (and only slightly larger in gallons) and my pH remains very stab1e at about 7.7 for a period of maybe weeks or longer. I have not only a spillover spa but two waterfalls and deck jets. I keep the pool heated to 86 to 88 degrees and the spa gets heated to 102 when I use it (which is about 3 times a week for about an hour or two.) I keep my CH high ehough (around 400ppm) to keep the SI slighly negative (helps slow scale buildup on the cell.) Both chemgeek's spread sheet and The Pool Calculator make calculating the SI easy.

I keep my TA at 70 ppm, borate at 30 to 50 ppm, pH no lower than 7.6 and only lower it back to 7.6 when it climbs above 7.8. CYA is kept at 80 ppm (Goldkine SWCG). FC is kept at 4-5 ppm. I only need to add bicarb once every 6-8 months (and the pool/spa is open year 'round.)
The recommendations that I made in the post you moved to the china shop have been proven to work over and over again, first at TFP and also at PoolSpafourm, not ot mention with my own customers.
For that matter, we had mentioned in passing once before that OnBalance ( Que Hales, Doug Latta and Kim Skinner) have dosage numbers for borax (both pentahydrate and decahydrate) in their tables for formula numbers and simplified dosage formula charts which sort of indicates that they use it in their salt pool and gas chlorination businesses or are at least familiar of its use to help stabilize pH, dontcha think? SWCGs are a bit more technical and their water balance requires a bit more precision that the dump and test method for optimum results. Rising pH is a problem and it can be successfully controlled, even with an attached spillover spa, negative edge, or other water features. It's not rocket science but it does require some attention to details.

[waterbear]

I Want to make sure you noticed I have an UltraPure Uv Ozone generator also. Didn't know this and had no information from builder, but went online to get product info. It's a UPP25, good for up to 25,000g pools, generating 0.146 gm/hr. Seems a bit of an overkill, but will reduce chlorine need and extend the life of the SWCG.

The UV ozone generator will not do much for an outdoor pool, will not allow you to run a lower FC level, and might actually INCREASE your chlorine demand (the amount of chlorine needed to be generated to maintain a specific FC level) because ozone destroys chlorine and vice versa. You might find that you actually need to set the cell to a lower output percentage to maintain the same FC with the ozone off than on! YMMV and a lot depends on the amount of usage (and organics) in the water. Test strips are notorious for not being accurate for both CYA and TA so wait until you get your test kit but you DO need to get your CYA up to 80 ppm (and maintain your FC at 4-5 ppm) . This will help with the pH rise indirectly since ti will allow a lower output percentage to maintain the FC level and that means less cell on time which mean less generation of hydrogen bubbles in the cell which means less outgassing of CO2 from that source of aeration which means slower pH rise.