My 650g plywood tank also Wetsuit

So I started my build about a few months ago. I didn't want to build and post at the same time but I did take a few pictures along the way.

The tank is 7'x5'x30" with two sumps under it. I incorporated an algae scrubber into one and a wet dry into the other. Everything is made of 3/4" hardwood plywood reinforced with fiberglass and coated with Wetsuit. I debated which waterproofing method and came down to Wetsuit and Pond Armor. I initially wanted to use Blue Max but didn't like the transparency. Pond Shield had fumes and I'm doing it in the basement so that was out. So it came down to PA and Wetsuit. PA being more expensive and Wetsuit being untested. After doing more research and this forum I decided to take the risk of using Wetsuit.

The floor of the area where the tank is was so uneven I had to pour 6 bags of concrete to get it level. If you sight down the 2x4 you can see one end has about 2" of new concrete under it while the other end doesn't.

Next came the stand. I used 4x4 pressure treated deck posts and 2x4, and 2x6's. I primed everything just to keep down moisture absorbing from the sumps.

The tank walls were a little awkward to build but I had some corner clamps which made things a lot easier and kept square. All seams were screwed with 2" gold drywall screws and glued with construction adhesive.

That corner brace is temporary and won't be there when the glass goes in.

Next came the fiberglass. I layered corners and seams 2-3 times thick. I used 10oz fabric with low vapor epoxy from US composites. The 3-1 pump ratio made it really foolproof. My past experiences were always hit or miss with not enough hardner or too much. The pump system was really helpful.

I also added some cross braces to the outside of the tank. I didn't do the entire outside because as I've read you don't want to seal the tank inside and out so you can see stains from leaks.

I wanted to add insulation under the tank and the side walls too. But how do you get a big piece of 1/2" sheet under the tank without 4 guys lifting it and sliding it in? That was a brain teaser. So I got out my car jack and lifted it up on one end, slid half of the panel under and jacked up the other end. Slid pvc pipe under it and rolled the whole thing together. Not a very good explanation but you get the idea.

Next came the Wetsuit. It was pretty easy to apply like slightly thick paint. It was thick enough where it didn't drip off the roller/brush when I really loaded it but thin enough to spread easily. If I had to do it again I would not use the Invisilink. It's just too hard to work with. It's like working with duct tape. It sticks better to itself than what you want it to. It also will leave seams and you have to try and minimize bubbles. The guy at Wetsuit told me to goop it on the bottom and spread it up over the fabric. If he didn't tell me that it would have been a nightmare to spread the wetsuit. In areas where I tried spreading directly over the fabric it stuck to the roller and came off the wall. The whole process was a mess and a PITA! Maybe I'm not skilled enough as an applicator but next time I will not use the fabric. If it was a big sheet instead of strips it would have been a little easier to manage.

I had a pretty long working time since it's water based. However when some edges of the wetsuit around the base of the paint brush started to dry it formed little clumps that would work it's way onto the surface and turn into a sticky mass. Make sure you have a few extra disposable brushes around to change. If you're doing a small tank it may not be a problem. Mine is large enough to take more time to apply so it became a problem.

You can seem wrinkles and folds in the fabric. Some of the wrinkles were from bubbles that I tried to smooth out and it stuck to itself. You can definitely see seams where I overlapped. If you want a smooth surface don't use the fabric and just use fiberglass as your strengthening support. I didn't really need any extra strength from the Invisilink but people kept telling me to use it with the Wetsuit. I got this huge roll has part of the purchase so I figured I'd just use it.

Now I'm just waiting for it to dry enough to crawl back in there to do some more touch up. With the tank, sumps and sump lids I only used around 2 gallons. I'm wondering if I used enough because I really gooped it in there.

It's actually 11/16" plywood.