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ladoladi
08-05-2012, 12:37 PM
Hello,

In March, we had our old pool resurfaced with a quartz aggregate and re-tiled. We also switched out some old equipment: filter and heater, and we switched over to a salt cell. We've been doing a good job of maintaining our chemicals and salt levels, taking a water sample every week to our local pool supply.

A few weeks ago we started noticing some rust-colored stains around the pool drain and thought that maybe we weren't putting in enough sequesterant, so we added more of that. But now the stains are everywhere, in the spa, along the seating area and the drain, and in the pool, around the drain and in other low spots... and we realized the 2 lights (one in the pool, one in the spa, both original to the pool) are completely rusted out!

We were thinking the lights were the cause of the problem, rusting out from the salt, but we've been reading through many of the very helpful forum posts about anodes and electrolysis and have just a few unanswered questions:

1. Our pool contractor put a zinc anode in our skimmer basket, but none at the pad/bonding wire. Should we hold him accountable for these stains on our 4 month old surface since he didn't properly attach the anode to the bond wire? BTW, the manual for the SWCG doesn't mention anodes at all, but our contractor has been doing pools for 30 years and this is not his first SWCG.

2. How long is a sacrificial anode skimmer weight supposed to last? I can't find this information on the product packaging or the internet. Would you expect it to already be useless after 4 months? This is what ours currently looks like: http://i.imgur.com/2rp81.jpg . It's mostly just covered in salt.

3. We're thinking the original pool builder never properly bonded the pool and spa lights--just left them grounded to the electrical system. Due to a lower ground potential than the rest of the pool equipment, they are rusting out before even the zinc anode in the skimmer basket. Is that a possibility?


Thank you.

PoolDoc
08-06-2012, 01:18 PM
+ A sacrificial anode has to be electrically connected to anything it was intended to protect. It sounds like that was not done in your case. Most contractors have no idea how an anode works. BUT your anode is hardly worn; an anode is 'used up' when the overall surface area begins to diminish. In your case, that would mean when the thickness of the anode started getting near 1/8".

+ It has not been established that even properly installed zinc anodes will reduce corrosion in a salt pool.

+ The stains you describe sound like iron, but unless you have exposed rebar, there's not usually any iron to corrode in pools less than 20 years old. Iron can enter the pool through your fill water, or through some low grades of pool salt. Under extreme conditions, the stainless steel in lights could corrode and release iron (and nickel, etc.) into your pool but that's not super likely.

I'll post some relevant boiler plate below.

Ben

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+ Get a cheap OTO (yellow drops) / phenol test kit, or if available at YOUR Walmart (check availability (http://www.walmart.com/ip/HTH-6-Way-Test-Kit/17043668)), get the HTH 6-way DROPS test kit, which is compatible with the Taylor K2006. Test the pool as soon and you can, and post the results. If you get the 6-way kit, ALSO test the water you FILL the pool with, especially if it's a well, and post THOSE results as well. (The HTH is the best available kit you're likely to find locally, but it's not the K-2006. It can only provide rough measurements chlorine levels above 5 ppm, and it measures "TOTAL" hardness, rather than "CALCIUM" hardness, which is not ideal.)

+ Having a good test kit makes pool care easier for EVERYONE, but is an ESSENTIAL tool for pools with problems. A good test kit means a kit that can test chlorine from 0 - 25 ppm, pH, alkalinity, calcium hardness, and stabilizer with reasonable accuracy. Test strips (AKA 'guess-strips' ) do NOT meet this standard. Some pool store testing is accurate; most is not. The ONLY way you'll know whether your pool store is accurate or bogus, is by testing accurately your own self. On the other hand, pool store 'computer' dosing recommendations are NEVER trustworthy -- ignore them. They are designed to sell more chemicals than you need, and WILL cause many pool problems.

+ We recommend the Taylor K-2006 test kit, which meets the requirements above, for many reasons. The HTH 6-way drops kit is a great starter kit, and is compatible with the K2006 (it's made by Taylor). There are a few alternatives; for example Lamotte makes an FAS-DPD kit that's OK -- but it costs 3x as much. But, we're not aware of any test that is better, and since we are all familiar with the K-2006 (and can help you with it) we recommend it exclusively ( Test kit info page (http://www.poolforum.com/pf2/showthread.php?16551) )

One caution for the 2012 season: Amazon does not stock the kits directly. So when buying at Amazon, Amato is our current preferred seller. However, they often don't list enough stock to last the whole day, so try order mid-morning. You should expect a delivered cost under $60 for the K2006A and under $95 for the K2006C. If you can't find that, wait a day.

+ Here are links to the kits we recommend (you can check local availability on the HTH kit, using the Walmart link):

HTH 6-Way Test Kit (http://www.walmart.com/ip/HTH-6-Way-Test-Kit/17043668) @ Walmart
Taylor K2006A (3/4 oz bottles) (http://www.amazon.com/exec/obidos/ASIN/B0002IXIIG/poolbooks) @ Amazon
Taylor K2006C (2 oz bottles) (http://www.amazon.com/exec/obidos/ASIN/B0002IXIJ0/poolbooks) @ Amazon



+ It's much easier to answer your questions, when we have the details about your pool in one place. We often 'waste' the first few posts back and forth collecting information. So, please complete our new Pool Chart form -- it takes about 30 seconds, but will save much more than that.
Pool Chart Entry Form (http://goo.gl/cNPUO)

ladoladi
08-06-2012, 10:22 PM
Thanks, Ben! I'll post soon with results of test kit.