Cargo trailer gray water tank mounting

I was able to mount two 20 gallon grey tanks, plumbed together under my 14' cargo trailer. Depth is a big limit, so that's why I needed side by side tanks. Measured dimensions I could work with then did searches for tanks.
As mentioned getting a vent tube up through the roof was problematic. I had built a shower stall/porta potty enclosure and ran the vent tube up through an edge of that enclosure.

never have come close to filling the full 40 gallons. 2 gallons for a shower at most, 2 gallons for dishes, can take a while to fill the grey tank.

I put 3 class a custom tanks on my trailer, they fit nice between the frame rails. Getting the vent up was the most problematic issue for me, I used 1.5" angle iron and welded up frames for them. 2x20gal for fresh and a 20 for grey, it's additional storage for my truck camper.

Might be easier to add just a drain line and get like 3 aqutainers. 20 gallons for a grey water tank is small. Especially if you have a shower. Its doable, but probably not practical.

Utility trailers are sometimes low on ground clearance. Be strategic on where you place it. The one you are looking at is 8.5 inches in height.

This is what I'm looking at:
https://smile.amazon.com/gp/product/B07LBB4RTF/ref=ox_sc_saved_title_10?smid=ANNYFJC2Y5PU4&psc=1

I guess there should be some kind of rubber on the straps?

RV water tanks

Tanks are generally held in by metal straps