Rust-Colored Deposits on AGP floor

[mlj1954]

My pool is a 17K gallon AG with vinyl liner. It has a sand filter. I have been maintaining an above ground pool since about 1995. My water is Crystal Clear. I do not use an SWG. Around 3+ years ago, my pool started developing rust-colored deposits on the bottom of the pool. If you run a brush across them, they will dissipate into the water. Some of them are hard to get up and you have to scrub over them with the vacuum and will leave a dark spot where the deposit was. A few spots have started to leave a little of the rust color even after running the vacuum. Over time, the bottom of the pool liner has developed numerous dark spots where these deposits always show up. The area that is most affected is the half of the pool that is closest to the skimmer and return jet. I have always taken water samples to my local pool dealer for analysis. I have changed the sand in the filter each year for the past 2 seasons. This year I replaced the laterals as well. After running the vacuum I always backwash thoroughly before turning the pump on to circulate. If I leave the pump off, the deposits will not start to show up until about 2 to 3 hours later and they are very small in size and number. After turning on the pump, within 15 to 30 minutes, I can see evidence of the deposits reforming again in force. If I vacuum to waste, I get the same result. I have treated for green, mustard, and black algae, multiple times using Banish, Spot Kill, and Yellow Treat. After each treatment, I would never introduce anything back into the pool until I knew if the deposits were coming back or not. They always come back. My local pool dealer finally agreed to send a water sample (both pool and make-up water) to BG for analysis. I was able to capture a good amount of the deposit matter and include it in the pool sample. The analysis report stated that I basically had DIRT and other debris in my pool. The mystery is that no-one can tell me where it's coming from. I am posting Pictures, http://s1214.photobucket.com/albums/cc498/mljpool/and a copy of the analysis report. The most recent analysis I have from my local dealer is as follows:
FC:9
CC:9
PH:6.7
TA:81
CH:236
Please help if you can.

 

[pepsiholic]

I fight this problem all summer. I can't say that it has ever lest a stain on my liner, though. The only thing I've found that helps is the use of skimmer socks and sometimes some kind of filter aid that you mix and put in the skimmer to try and catch the finer stuff. It doesn't rid it completely, but it helps. The skimmer socks are great for catching pollen. I change it every day, after the sock dries, you can pull the pollen of like dryer lint. I also run the vac every day. It's just very fine dust that's blowing through the air and settles in the pool.

 

[southgaamy]

Did you ever solve this issue, because I have the EXACT same thing going on and am about to pull my hair out. I just can't believe it is dirt, because I have a robot cleaner that I can run every day and the stuff still returns. If you were able to solve this problem, please share what helped. Thank you.

 

[domct203]

I constantly have a fine dirt accumulate in the seams & wrinkles in my liner. I just brush & vacuum. It doesn't stain however.

I believe it is from the two large trees that are over the pool.

Do you have any trees overhead, or close by? Is there any dirt or debris that settles on other surfaces like chairs, tables, windowsills, etc?

There are many trees on the surrounding properties & I have to power wash the house spring & fall. I'm sure that it what I see in my pool.

Dom

 

[Texas Splash]

mlj,looking at your original post here, there are a few things that catch my eye and/or you may want to consider:
- Your test results are concerning. For example: Your ph is way too low. It should not be below 7.2. That needs to be raised right away. Also, you show a combined chlorine (CC) of 9. If that's correct, that means there's a significant amount of organics (i.e. algae) being consumed in your pool right now. A TA of 81 seems to indicate this testing is from a pool store, not your own test kit - is that correct? Do you have either a TF-100 or Taylor K-2006 kit? I didn't see it in your signature.
- If this testing was from a pool store, they should have advised you of the low pH and other issues. So if this is the case, I would highly encourage you to obtain your own (proper) test kit from TFTestkits.net. We've seen time & time again where pool store testing is inconsistent at best.
- We need to know your current CYA reading. Do you have that?
- Do you fill your pool from well water, or is strictly from city?

I will try to open that water analysis attachment, but I couldn't while making this post. I may have another comment after reading it, but we'll be looking for your replies as well.
Oh, and by the way ..... welcome to TFP!

 

[Texas Splash]

Okay, that was easy. You have way too much iron in your water. Please review the following info and link/page:
Pool School - Metals in the Water and Metal Stains

Once you've added chlorine to the pool, it oxidizes nearly all the iron to ferric iron, then forms iron oxides. Now the approach is to physically remove these precipitates either through vacuum-to-waste, through sweeping to get to the filter (or to skimmer socks or batting material). Then you'll be left-over with a smaller amount of iron in the water at which point you can either use a metal sequestrant or physically remove it with something like Metal Free that tries to capture and precipitate more into the filter. You'll want to remove this extra metal to prevent staining that can occur if the pH rises. Also, you may introduce more metal from evaporation and refill, so try to use a pre-filter anytime you add water.

Iron in the water will be an on-going issue unless you are able to drain and have new water (without metals) trucked-in to your pool. A balance between pre-filtering and sequestrants will help significantly.

Also consider the notes above about your own test kit and adjusting your items to the recommended levels based on:
Pool School - Recommended Levels
Pool School - Recommended Pool Chemicals

Good luck!