Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 6 of 6

Thread: TX Torrential rains & my recent SLAM

  1. Back To Top    #1

    Join Date
    Apr 2015
    Location
    Katy, TX
    Posts
    52

    TX Torrential rains & my recent SLAM

    Hi, so I just finished my first SLAM 2 weeks ago and enjoyed a clean clear pool with great numbers until the storms hit. Monday night we had torrential downpours overnight in Houston, between 6-10 inches fell, and I woke up to a Pre-SLAM looking pool, in just 12 hours! The numbers and picture are below, I'm curious, can that much rain bring down enough junk from the air to cause an algae bloom, or could it have been overflow from the surrounding ground running into the pool because it couldn't drain away quick enough? I'm thinking the latter, but have to ask...

    Before the rain (monday at 7pm) , my numbers were:

    pH 7.8
    CYA 85
    FC 8 (Target 9-10, added bleach to bring up to 12 overnight)
    CC 0
    CH 225
    TA 100

    After the rain, my FC reading on Tues morning was 9, probably due to dilution from the rain, but certainly high enough to keep algae away, right? Is there any way algae could bloom in 12 hours, or should I assume it was just runoff from the surrounding ground? I've added bleach to keep the FC at 12 or above since, and CC still is very near 0. I've seen my filter pressure raise 25%, 17 up to 21, so I know it's clearing the junk out, but I'm "shocked" at how nasty the pool looked in the morning after all the rain, check out this pic... Thanks for any help/guidance, Jeff
    Attached Images Attached Images
    Katy (Houston, TX) - 15,000 gallon In Ground free form kidney shaped 30'x15' pool with Pebble surface. Spa - 8' round with waterfall. Hayward Swimclear Cartridge filter (not sure which model though - maybe C3025?). Pleatco replacement cartridges x 4, 1.5HP Hayward Century Pump, Hayward Booster Pump (model 6060). Chlorine tab dispenser, which I won't be using. Polaris cleaner. TF-100.

  2. Back To Top    #2
    smforte's Avatar
    Join Date
    Sep 2013
    Location
    Montgomery,Al
    Posts
    668

    Re: TX Torrential rains & my recent SLAM

    From the picture it looks as if you have a slope to your yard so I would assume run off. You need to SLAM..(maintain for your CYA LEVEL) ..If your pressure has risen 15-20% I'd backwash first before slamming. Your filter is catching the junk.
    Montgomery, AL
    27000 16 x 36 IG, Vinyl, Grecian, Hayward Sand filter, 1 HP Pentair whisperflo motor, Aqua Genie filter not by choice, no extra jets, Dolphin s300i robotic cleaner,Taylor K 2006 test kit, speed-stir which I couldn't live without!

  3. Back To Top    #3
    Mod Squad pooldv's Avatar
    Join Date
    Aug 2012
    Location
    DFW, TX
    Posts
    23,999

    Re: TX Torrential rains & my recent SLAM

    I would bump up FC to 20 or 25 and run the filter 24x7 for a couple of days and see what happens. You could do an OCLT to see if there is additional chlorine demand.
    TFP Moderator
    If TFP helped you or saved you money - Become a TFP Supporter! <--Click here
    2012 build and pics, 20k gal gunite, black onyx pebblesheen, OK flagstone, IntellifoVS, cart filter w/Pleatco, IC40 SWG, Solartouch, 5 12'x4' solar panels, HP50HA heat pump, 8mil solar cover, borates, TF-100 test kit, SONOS, Doheny's Discovery Robot, hot tub on bleach

  4. Back To Top    #4
    Patrick_B's Avatar
    Join Date
    Jun 2011
    Location
    Midland TX
    Posts
    15,001

    Re: TX Torrential rains & my recent SLAM

    Your assumption is correct. One of the biggest misconceptions is that Rain destroys pool chemistry, when in fact it has little effect. Mind you, these are some heavy rains, but runoff is another issue. I can't tell how much runoff you might get from that picture, but what often happens to people is that they are on the very edge or already starting a bloom when they get a good rain. Judging by the picture, I would say this is a lot of run off because...look at the spa. It looks pretty nice from here.

    In any case you ought to at least begin a SLAM. If you have to keep SLAMing, 85 Cya is really going to take a lot of Chlorine. As DV says, 20-25 but that will take a lot if you have to sustain that number, so if you are going to have to keep this going, you really want to bring that number down some.
    TFP Moderator
    Essential Links:
    ABC's Of Pool Chemistry, Test Kits, SLAM Your Pool
    28K Gal IG FreeForm, CLI Quartz, Pentair 36"SF & VS Pump, Dolphin M5, Rheem

  5. Back To Top    #5

    Join Date
    Mar 2015
    Location
    Baton Rouge, Louisiana
    Posts
    92

    Re: TX Torrential rains & my recent SLAM

    Patrick, it doesn't rain in Midland...
    26000 gallon Kidney shaped gunite pool. Older pool with deep dive well, nice diving board and tall slide. 31" Hayward pro sand filter with Pentair 1.5hp pump. Testing with the TF-100 plus test kit. Using a Dolphin Nautilus pool cleaner robot, next to bleach, my pools best friend.

  6. Back To Top    #6

    Join Date
    Apr 2015
    Location
    Katy, TX
    Posts
    52

    Re: TX Torrential rains & my recent SLAM

    I figured it out, somewhat. I suspect with 6-10 inches of rain, I probably did get some run off from the yard, but there's more. We had another big rain storm last weekend, and I noticed my yard and pool patio drains were slow to drain and I saw them back up back into the pool.

    If you look at the pics, you'll see the dirty water draining back into the pool. The second pic is the yard drain, which I think is connected to the pool patio drains.

    So, my next question is, could these drains be semi-clogged? Is it possible to drain those? I guess it's possible that they just can't keep up with the high amount of rain when we have big storms, but that seems unlikely, we get some big storms in Houston, I've gotta think they were made to keep up with the rain, and certainly not to drain BACK into the pool?

    Anybody seen this before?

    Thanks, Jeff
    Attached Images Attached Images
    Katy (Houston, TX) - 15,000 gallon In Ground free form kidney shaped 30'x15' pool with Pebble surface. Spa - 8' round with waterfall. Hayward Swimclear Cartridge filter (not sure which model though - maybe C3025?). Pleatco replacement cartridges x 4, 1.5HP Hayward Century Pump, Hayward Booster Pump (model 6060). Chlorine tab dispenser, which I won't be using. Polaris cleaner. TF-100.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •