New Tub Already Has A White Film. Really Not Slimy Though

[TubInTexas]

Hello all,

I am brand new to forum. I have been reading quite a bit since Thanksgiving. My new tub landed on Dec 15. Got it filled and was trying to follow Nitros Approach to Water Maint. Got it looking pretty good (I think). But, It was christmas and we got busy. Never got in it. Went out to check on it one evening about Dec 30th. GFI was tripped. Turned out heater went to ground. Brand new tub. Im in the electrical trades. I guess it happens. No slice valves. Never got in it but had to drain it, replace heater, and refill.

Finally got chems back in and water fairly acceptable (I guess). I have really soft water. Used 8 oz of damp rid. This only brought it up to 73ppm Hardness. Pool store said it was not critical since it wasnt a pool. So I stopped there. TA starts out very high. Used 8 oz of spa down. Still reads high along with Ph on strip. Trying to calculate cya using DiChlor then go to bleach. Have used 50 grams of it so far on this refill.

Me and wife got in it once last week for 30 mins. FC was 5 before. Forgot to add any til next day and it read 0. Added 11g kept up 3-5 ppm FC ever since. Wife was in last night for 30 mins. Added 7g after. Just using test strips.

Now for the question. It is a 330 gal Cal Spas AM630 BTW. It only has 1.5 hrs of bather use. It seems to have a thin film that is actually kinda rough. Not really slick feeling. What is the likelihood it could have white slime OR what else might it be?

Thanks so much in Advance for any help you might provide.

[chem geek]

The main reason to use 120-150 ppm CH in a spa is to help prevent foaming. If you do not have a foaming problem then you don't need to raise the CH.

You need to be more aggressive with lowering your TA by following the procedure of aerating at low pH and adding acid. See Lowering Total Alkalinity.

50 grams of Dichlor in 330 gallons would increase the CYA by 20 ppm.

If you have never used Ahh-Some I suggest you do so. Both the new spa as well as the period of time with no chlorine could create biofilms and those are difficult to remove with chlorine alone (though superchlorating can help, the use of Ahh-Some is more effective for their removal).

[TubInTexas]

Thanks so much for your reply. I have learned so much from your posts already. The manual that came with it said do not use a chlorine shock. I took that to mean do not super chlorinate. I kind of did super chlorinate any way on the first batch of water. Then I lost a heater. Hopefully a coincidence. I dont know how super SUPER really is. I got it over 12 FC. What number would you put to it?

I will have to order some ahhhsome. Will I need to change the water out when I use it?

I found another site that said high ph could cause scaling. I dont know that I had enough hardness to cause that though. But my ph is definitely high. It seems more rough. It is not white on the sides. You cant see it just can feel it. But when I scrape it up with my finger it is a build up that is white. If I rub it between my thumb and finger it disappears and does not feel slimy.

I hope it is just that I have gotten paranoid reading all the biofilm posts. And, I am, lets say, ummm, germ aware. Definitely not a germ freak though, no no no. Insert denial here

Also, if you dont have Boric acid, how do you calculate amount of acid needed to ofset 20 Mule Team Borax to achieve proper ppm for 330 gallons?

Thanks again

[chem geek]

The loss of the heater was probably a coincidence since 12 ppm FC is not very high though it partly depends on whether there was any CYA in the water. That is, if you had freshly changed water and used unstabilized chlorine only, such as bleach or lithium hypochlorite, then such chlorine is too strong though even that by itself would cause the heater to fail. If you used Dichlor for your "shock" then that should not have been a problem since the CYA would have moderated the chlorine's strength.

With low CH and a low TA you shouldn't have scaling even with a high pH unless it was VERY high -- much higher than even 8.0.

If you collect some of this rough-feeling stuff and pour some acid on it outside the spa, if it fizzes then it's calcium carbonate scale.

You can calculate dosage using PoolMath. In 330 gallons, for 50 ppm borates you need 19 ounces of 20 Mule Team Borax with 9.3 ounces of full-strength Muriatic Acid (31.45% Hydrochloric Acid) or about 13 ounce weight (9 fluid ounces volume) of dry acid (93.2% sodium bisulfate). You'd split into at least 3 dose pairs adding acid, then borax, then acid, then borax, etc. making sure it gets mixed each time in the spa water with good circulation.