SWG w/ Hi TDS?

[marcs]

As I plan the installation of a heat pump, it may also be time to reconsider the addition of a SWG. The six-year-old IG plaster pool holds 17k gallons and with an automatic cover it is always covered. Despite the mild climate on California’s Central Coast, the solar panels keep the temperature at 85-90 degrees for the five to six month swimming season.

The extreme amounts hydrogen sulfide in our well water is challenging to treat; however the treatment does not change the hardness of 900 ppm or 60grains, nor does it alter the Total Dissolved Solids at 2,000 ppm.

Hayward’s inline feeder doesn’t work, and most of the chlorination has been way of liquid or Leslies’ granular, and pucks in a floatie. On a weekly basis I’m using about 2 gallons of liquid or 2 pounds of granular, and 3 pucks in the floatie. I don’t recall the chemistry from last summer, however the CYA was off the charts. The guy at Leslies is familiar with my situation, and believed that the SWG would make matters worse with the high TDS, and hence the current chlorination regime.

But now that I’ll be doing some work, I’m open to reconsidering a SWG. Is the TDS really an issue? If not, what brand and size of SWG is best?

[chem geek]

Not only for considering an SWG, but in general TDS itself doesn't matter. What matters is what the TDS is composed of. You already pointed out the single biggest problem for an SWG (in terms of scaling) and that would be a high hardness level, though specifically it is the Calcium Hardness (CH) that is the relevant number. The other very important factor is Total Alkalinity (TA) and pH though the latter is the most easily adjusted.

So I wouldn't worry about the TDS, but get a complete set of test numbers: pH, Total Alkalinity (TA), Cyanuric Acid (CYA), Calcium Hardness (CH) ideally using a Taylor K-2006 test kit that you have or purchase. My guess is that with Total Hardness at 900 ppm the CH will be somewhere around 550, but this can vary a lot in different waters so testing is really required. Even if the CH level is on the high side, you will probably be able to mitigate that by having a lower TA which is something you'd want in an SWG pool anyway.

So, let's see those numbers!

Richard

[marcs]

Chem Geek,

Good points, now that I've finally figured out how to obtain quasi clean well water for domestic purposes, I suppose that it's time to finally getting around to accurately assessing the pool water, and simplify the maintenance. That said, the Taylor 2007 isn't readily available here in San Luis Obispo, we have one local shop and they can obtain the 2006 or '05 kits, or could compile a kit relevant to my specific needs. Being the only local guy, it would be wise to foster a long term friendship. Thus if I can support him, as opposed to the internet I would do so.

On a different note, and I should probably make a new post, what situations determine the usage of swing check valves, as opposed to spring check valves?

Any thoughts?

[Poolsean]

Swing check valves are also called gravity check valves simply because there's a weighted flapper that relies on gravity to keep the check valve closed. This is mostly used for backflow prevention with low backpressures...again, this is gravity.
A spring check valve is mostly used when a more positive seal is necessary, or in instances where a controlled flow on a bypass line is needed, such as with the Pool Pilot manifold assembly.
Spring check valves are rated at different lbs of backpressure. Check valves for spa blowers are usually 1/4lb. For chemical backflow prevention are usually 2 lbs. For hydraulic flow control is usually 5 lbs or more.

What application are you using the check valve for?

[chem geek]

Since you are talking about an SWG pool, then you'll also want to measure the salt level which can be done with the Taylor K-1766 or with an Aquacheck test strip (one of the few tests that actually works well with test strips). This will let you know how much additional salt you need to add to get to the 3000 ppm or whatever recommended level for the SWG.

[waterbear]

FYI, Taylor does not make a testkit with the part number K-2007! The kit you want is the K-2006 (FAS-DPD chlorine titration test) and not the K-2005 (DPD colormetric chlorine test).

[chem geek]

On Taylor's website they show the K-2007 as a California Regulatory kit. It's probably an uncommon kit.

[waterbear]

I stand corrected. Was going throuight a Taylor price list from work and that kit is not listed. Should have checked their website!

[CarlD]

The equivalent of the Taylor K2006 is the Leslie's
Chlorine FAS-DPD Service Test Kit from Lesliepool.com
It uses Taylor reagents and is re-branded for Leslie.

Whatever kit you use must have the FAS-DPD Chlorine test, not the DPD or OTO Chlorine test. Both Taylor and Leslie's sell the individual salt test kit too, again, both made by Taylor and re-branded for Leslie's.

Just alternatives.

[chem geek]

Just FYI. The cheapest Taylor K-2006 kit found on the web (that I know of) is here. The TF100 kit from tftestkits.com here is equivalently priced per use as it has 36% more volume of reagents, though the kit is different in some ways than the K-2006 kit as shown here.

Richard