New supporter - first test results k-2006

[jayquinty]

New supporter, and 11 year old pool owner here. I have been reading feverishly for the past week or so trying to get a handle on TFP methodology and all the chemistry. I "thought" I had a good understanding of pool chemistry, but I've learned a ton in the last week or so.

My pool is an 11 yr old 22k gallon IG, pebble tech, with a 60sf DE filter and SWG. My salt level (according to my fairly new cell) is 3400 so that should be good. Right now, my SWG is awaiting me to repair the bad varistor on the board, so it's turned off. I'm currently floating 3"tabs and use liquid chlorine as needed to boost, etc. As soon as I'm done typing, I'm going to go pull the tab floater out of the pool since I have a possible overload of CYA. More on that in a minute.

Last week, I ordered and received my K-2006 kit and ran my first set of tests. Here are my results:

FC 6.5
CC 0.5
pH 7.4
TA 110
CH 750
CYA 100*

1st overnight chlorine loss test showed a loss of 0.5 FC.

OK, so I have a few Q's.

First, I have the older style CYA test kit. It's the larger size tube that you fill up halfway with pool water and halfway with reagent, lift the plunger up and down for a minute, then make the black dot disappear off the plunger. I tested my water with that kit and I got 60ppm. I then tested with the k2006 and got 100+. I'm not at home so I plan on doing the 50/50 test with pool and tap water when I get home to get a more accurate reading. My question is how in the world can I be getting such drastically different results with these two kits. The old kit uses the same methodology as the k2006, so I'm scratching my head here.


Second Q. I'm wondering about my CH level. I tested our tap water and it has a CH of 250. My pool water is original so I haven't changed it in 11 years. My pool water is sparkly clear right now, and I have eliminated the algae that I had a couple of weeks ago when my SWG quit working and I didn't pick up on it quick enough. Other than the typical faint white line on the tile at the water line, I'm not experiencing any heavy scaling. Well, the exception is where the water trickles over the 5' wide opening from the spa into the pool. I have real rock spillway, and I do get some heavy white scaling in a few places. Do I need to do a partial drain to get the CH down? My thinking is that if my CYA is over 100, then I'll maybe do a 50% drain to kill two birds with one stone.

I ran out of time here, so gotta go for now. I appreciate all the info I've been able to glean from you all thus far. I'm glad I was able to support the forum and hope many of you lurkers will do the same. Looking forward to all your help.

Thanks
Jay

 

[jayquinty]

Just re-checked the pool and I got 850 on the CH. The result depends on when it actually turns blue versus purple. Wife says its blue @34 drops in a 10ml sample which is 850ppm. It's very subjective though since its dark purple at 30 drops. Strongly considering at least a 50% drain and refill. I can get a variance from the city for the extra water. They have us over a barrell for water in socal and heaven forbid if you use more than your allotment . It might make sense to go a complete drain and fill to get CH to 250 and start fresh again. Cost would be about $60 for water and $60 for salt. I have extra CYA so no cost for that. What do the experts recommend? My water doesn't look bad. In fact, it looks really good!

Thanks
Jay

 

[jblizzle]

Welcome to TFP!!!

Not sure how no one responded yet ... other than I am not really sure what to say

I have no idea why you are getting different answers. Were you doing the tests in the same lighting? The CYA test should be done outside with back to sun with the tube at waist level. This is really what set the next step. If the CYA is 100+, you really need to get that lowered, almost more important than the CH.

Depending on your location, you may have the option of Reverse Osmosis treatment on the pool. That would lower both the CYA and the CH and the salt, etc with less water loss. BUT, it is likely to cost more (like $400 or so).

If you can keep the pH and TA low, then you can compensate for the high CH for awhile. But the high CYA can become a problem if algae starts. And you can not do RO if the water is green (I think).

 

[Donldson]

If your CYA is over 100 then replacing some water to get that lowered to 70-80 and get your CH lowered would be the best route. If you can do it for roughly a hundred dollars then it sounds like a good plan to me personally. Really at that price reverse osmosis isn't even worth considering.

 

[jayquinty]

<<I have no idea why you are getting different answers. Were you doing the tests in the same lighting? The CYA test should be done outside with back to sun with the tube at waist level. This is really what set the next step. If the CYA is 100+, you really need to get that lowered, almost more important than the CH.>>

Yes, similar lighting. The only thing I can figure is the reagent on the older kit is about 6 months out of date, since I didn't test for CYA that often before so I wasn't using it up very quickly. Now that I realize how integral it is, I'll be testing it more frequently using the Taylor kit. That being said, I did a 50/50 test using the Taylor kit and I came up with 50ppm, so my CYA is 100ppm. I'll be ditching the old kit! Since I know that my CYA level drops slowly over time, and being that I don't have any CC in my water, I'm not sure if it's worthwhile to do a partial water drain/refill to get it down to the recommended 70-80 for SWG pool. I may just let time take its course and keep my FC up over 5.

BTW, I didn't mention that I have 25ppm of borates in the pool currently. Put half of them in last week because the local Wal Mart only had 8 boxes of 20MT. Figured I'd do it in stages, but since I put those 8 boxes in, I got my Taylor test kit, and now I'm in a quandary over whether to do a partial drain/refill to reduce the CH. Based upon the values I'm getting on the pool calculator, it doesn't affect the CSI all that much with all other variables being factored in. I guess I just need to make the decision to stay with the high CH for a while longer and add the rest of the borates, or to just bite the bullet and do a complete drain/refill and start from scratch. It's definitely cheaper than RO if it's $400 for a treatment.

Thanks again for the help.

Jay

 

[jblizzle]

You could maintain the FC above 5ppm and likely be fine for the rest of the year. Any backwashing will slowly help to reduce the CYA as well.

The pH is the largest driver on the CSI, so keeping it a little lower will help. BTW, you should have lowered the TA to around 70ppm BEFORE you started adding borates. The TA adjustment is step 1.