***** OTHER POSTERS PLEASE NOTE => THIS IS A *LARGE* *****
***** COMMERCIAL COMPETITION TYPE POOL *****
Here's a picture:
http://www.gjsentinel.com/images/pho...ar_600x500.jpg
www. gjsentinel. com/images/photos/ imgkit_sized/pomar_600x500.jpg
www. mesastate. edu/purchasing/documents/AppendixAEquipmentSpecifications.pdf )
Note for Chem_Geek: they're using UV for chloramine reduction, and have combined a cal-hypo tablet feeder with CO2 based pH control! They did install floor inlets, so they have better than average circulation.
Hi MAV;
Thanks for subscribing. Let me caution you, as I did others here (above) your pool is quite different from what all but a few here have worked with. The underlying chemical principles of pool care remain the same, but there are some very large practical differences.
OK. Where to start?
FIRST:
Unless you have an exceptionally well designed circulation system (possible), your water volume is so great, and the distances from flow input so long that the pool will not have uniform mixing rates. This will tend to lead to variations in chemistry.
SECOND:
Your pool will have a greater tendency toward 'wobbly' pH than most large indoor pools. The reason is that your "acid" is a partially soluble gas that will tend to exit the pool water during aeration (ie, during warm-ups at a big swim meet!), causing the pH to rise. (Chem_Geek, will the TA also tend to rise?)
THIRD:
Because you are using CO2 (via carbonic acid) to lower pH, AND calcium hypochlorite to chlorinate . . . you are going to have problems with hitting your contract targets:
pH 7.4 - 7.6
Calcium Hardness 200 - 400 PPM
Total Alkalinity (Calcium Hypochlorite) 60 - 80 PPM
Langelier saturation index -0.3 - +0.3
( http://www.mesastate.edu/purchasing/...ifications.pdf )
Frankly, I'm not sure that it's possible, without changing to a different source of chlorine or a different source of acid. Trying to operate a pool by feeding carbonic acid (HCO3) and calcium hypochlorite which reverts to calcium chloride (Ca(OCl)2 => CaCl2) will be an interesting challenge.
THIRD:
If you have a Chemtrol PC3000 or equivalent per the specs . . . you do NOT have a system that can "measure" chlorine levels; you have a system that infers (guesses at) the chlorine level based on the ORP. This is a half-way reasonable thing to do, with an indoor pool (it's altogether stupid on an outdoor pool!), but you still have to remember that your system measures ORP, not chlorine. And ORP does NOT equal chlorine, though higher chlorine levels do tend to cause ORP to increase.
FOURTH:
pH / ORP controllers like the PC3000 have to be calibrated when they are new, and frequently, thereafter. When I was selling a competitor product, I ended up locking the boxes, and putting tape over the windows, because the operators were reading the gauges rather than doing actual water tests . . . and a result, failing to notice when the unit had drifted out of calibration.
FIFTH:
If you are testing pH with a meter, you MUST calibrate your unit with fresh buffer solution REGULARLY. Meters *can* be more accurate than 'eyeball' colormetric tests, but unless you calibrate them regularly, they tend to be much LESS accurate. On the other hand, with an 'eyeball' test kit using phenol red drops, you can't reliably distinguish 6.8 from 7.0.
SIXTH:
Your Facebook indicates you are a student there. If so, I need to be careful how I answer you. Someone is very proud of that pool and its design (and there are some very good features), but such a person doesn't really want to here things like, "You never should have spec'd and installed an XYZ system". To put it another way, there's advice I could offer that would be appropriate for someone with total authority over the facility . . . but giving that advice to a student employee would only get him in trouble if he tried to follow it.
So here's what I suggest:
1. Make sure your pH tests are valid -- either use a wet test OR make sure your meter is (and stays) properly calibrated.
2. Find out if your pool finish contractor (Diamond Brite) is still on the hook for the finish warranty. If he is, make SURE you stay within (and log!) his requirements. Otherwise, if you stray outside much, and if there is ever a problem with the finish, he'll likely get off the hook by blaming it on the 'pool maintenance' errors.
3. Find out who's responsible for maintaining calibration the Chemtrol unit.
4. Do NOT allow your pool to rise in pH quickly -- it could turn milky instantly.
5. Let us know what you find out, and how I can help you.
Ben
PoolDoc
Bookmarks