Unintended consequences....... Oh, my. OJ messed up, but I'm not really understanding all the issues. Guess I'll keep rereading the post and maybe more of it will sink in. OK. The plan is to build a 9by14 GH on the south side of my home with a window that will open to the house to help with temp control in winter months only. Because a fireplace burns in the house pretty much all winter, the house is VERY dry. I did not anticipate the additional humidity would create serious problems. Do you think the window opening or the house siding could lead to the type of damage OJ talks about? I would love to keep the GH warm enough for tomato plants to survive the winter, but may add extra insulation around the tomato to limit the space that gets the higher temps. I brought a container in from the garden with a grape tomato in it. It sits in front of what will be the window into the GH. The tomato started blooming first of Feb. My experiment this year is to take cutting, with blooms, from that plant to root. Just trying to see if the blooming cuttings result in an earlier production of fruit. If so, I'll plan on keeping choice tomato plants going all winter. I LOVE homegrown tomatoes! Paul Robson is my most favorite of all time.

1) Bottom drains are not required in residential pools but are very useful to have. If you ever need to dump water below the skimmer, it's a PITA without one. If, for any reason, the water drops below the skimmer, without a drain line that the pump can run off, you can't easily run the pump to circulate. The question I have about company #1 is will they be putting in two drain pots ties together. Unless the existing drain is tied to the skimmer, that type of modification may require two drains, three feet apart. This is as the result of a relatively new law called the Virginia Graham(SP) Baker Act of 2007, or VGB 2007. This is law created some Federal requirements for swimming pool construction. One part states that there may no longer be constructed any submerged suction outlets that have a single source of suction or shall be be large enough that a person cannot block it and become entrapped under water due to suction. Additionally, the covers for these suction outlets shall have passed a testing procedure and proven effective against entanglements, such as could happen with long hair or necklaces to a specified flow rate. The above work can be done without it screwing up the pool's integrity. Is it easy, no. If it was, Grandma would have done it. If the existing drain is fine, leave it and replace it's cover with a new VGB compliant cover. Since the old style is no longer available in the US legally, it does make the existing one safer. There is no requirement that I know of that requires retrofitting the new construction codes to existing residential pools except during certain repairs. Permanently sealing off an existing single main drain suction outlet is permitted. Replacing a single drain with a similarly sized one, assuming we're talking about a standard 9" drain, must be turned into a dual drain unless the single drain is tied at the skimmer so as to prevent a single source of suction underwater. It's a mouth full, I know. Sorry, but the VGB act is a good thing in that it helps make pools and spas much safer. 2) Pebble Tec's standards and controls are much stricter. This makes it a better product. 3) Hydraulic=oil . Leaks happen and can be messy and costly. Clean up can be costly. I prefer the rope and pulley systems that pull the cover along it's tracks and then use a direct drive to turn the spindle that reels the cover back. 4) I would be concerned with how the artificial and dog pee/poop and potential staining and odors. Scott

I kept looking at the subject of this post and thinking, every pool I installed, had a main drain. But that was back in the late 70's. Now in most places two main drains tee'd together 36" apart is a requirement. It's to reduce the possiblity of entrapment. The covers are to be asme ansi approved and have the ansi number stamped into them. Most main drains we put in, and most pools that I have worked on, have the plumbing to the main drain comming out of the front port of one of the skimmers. If you don't use the float valve in the bottom of the skimmer, nothing happens. So I got to thinking. You don't actually drain the pool with the main drain. Most pool cleaners do better without a main drain grate to get hung up on. If you don't have a main drain, no one can get caught in it. So no main drain, no problem.

Thanks cascade. I can plug the skimmers and return lines. It's the two drains the are going to be the real challenge. They are 9 foot down in the deep end. I agree tigpie. I wish I had master shut-off valves on each line. The pool was built in 1986 and was, overall, done very well. It is about 60,000 gallons with two separate systems (the spa is a completely separate third system). Each of the two pool systems has a 3hp pump, DE filter, backwash tank, chlorinator, supplemental heater, main drain, a skimmer and a return line as well as it's own set of solar tubing integrated into the pool deck. There are a total of 10 2.5" PVC pipes coming out of the pool wall that are reduced down to 2" and the entire pad is plumbed with 2". All the pipe, valves, filters, chlorinators and actuators will be replaced as part of this modernization. I just wish I had 10 shut-off valves on the pool wall to be able to work in peace. I plan to add them as the first step and that's why I posted this question. Anybody had any success blocking off main drains. If so, how did you do it? Thanks. Tom.