Bicarb start up

[carolina pool]

After reading the info here and having a couple of conversations with onbalance, I've decided to try a bicarb start for the medium grey plaster pool we are plastering Tuesday. It seems that it would result in a smoother and longer lasting finish. Over the years we have used the traditional and acid start ups for colored plaster.

I acquired the 55 gallon barrel from a friend in the tree business and will cut it up and turn it into a slurry tank. I will do my best to log reports of the chemistry and conditions as they are observed and report them to this thread. I have ordered the TFP test kit to monitor the process.

These are the results from testing makeup water using Aquacheck test strips:
Total Hardness 0
CC 3
FC .5-
PH 6.8
TA 20-
CYA 0

Since I can only get it started and babysit the slurry tank for a couple of hours, we have decided to start with two 50lb bags of bicarb sliced up in the bottom of the slurry tank to have a level of controlled dilution of the bicarb.

Figured this might be a good wintertime discussion and experiment.

 

[257WbyMag]

What was the issue with the acid starts that caused you to want to do the opposite?

 

[carolina pool]

I am assuming the bicarb start up will be less aggressive on the new plaster, minimize the mottling, reduce the amount of brushing and require fewer adjustments in the chemistry. If I can provide a smoother, harder finish for the customer and spend less time and make fewer trips to the jobsite, it makes a lot of sense to put in a little more effort upfront.

In this case the tap water is very aggressive and the customer won't be using the pool for a couple of months, so it seems like the right conditions for a bicarb start up.

I only see upside to the process with no risk on the downside.

Is there a downside?

 

[carolina pool]

Considering the difficult weather conditions all went well with the bicarb start up. We covered the pool after plastering on tuesday because the weather forecast was not too predictable. It rained slighty 12 hours and 15 hours after filling and then we got 2 inches and 40 mph winds 24 hours after the filling started. It was full in about 32 hours.

I was fortunate to have a very willing customer to participate in the process. Otherwise the delivery system of the bicarb would have been very difficult and uneven. He would go out about every hour and stir up the slit bag of bicarb in the bottom of the barrel except for a few hours when he had to sleep. (It reminded him of having a newborn in the house)

The downside of this method is the delivery of the bicarb as mentioned above and waiting 6 hours after the plaster is finished to start filling. That means filling starts in the dark which makes it harder to test the water in the barrel along with other issues related to darkness.

The upside is that there is virtually no plaster dust which indicates to me that the plaster is indeed harder and will hopefully reduce the need for heavy constant brushing (which nobody likes to do).

In the process of monitoring the water tests it became certain that there is an obvious discrepancy between the test strips and the TFP test kit. I was testing during the day with the strips and the customer was testing at night in his kitchen with the TFP kit. He was constantly reading 2-4 points higher on the ph and 20-40 higher on the TA. Yesterday we tested them side by side from the same spots of the pool and got the same discrepancy. The TH color on the test strips is very difficult to discern the difference between 0 and 100, so I was reporting 0 to onbalance which he found hard to believe and when the customer started testing the CH it has consistently read 50.

The pool looks great and the customer is really happy, but I think he is an exception to the majority of customers that would be willing to put this much effort into it.

 

[JasonLion]

Is there a downside?

There are only three negatives (that I know of), all minor. First, it seems to be a little more work. Second, it appears to require some special equipment (not much, but at least a tank to mix fill water with bicarb). Finally, no one has ever written up a description in a format that a home owner could actually follow.

The advantages seem to easily out weight the disadvantages, at least if you know the correct procedure.

 

[carolina pool]

It is certainly more work in the first 48 hours but if the brushing time is greatly reduced it could be a net positive in man hours. This remains to be seen.

When we truck in the water, it will make a lot of sense to mix the bicarb in the tanker which could make the delivery system near perfect and much easier, although it would have to wait until the morning after.