Two tanks set up

Hello everybody, I’m currently starting a new trailer build and would like to use both my tanks, I have a 35 gallon and a 65 gallon tank, I was hoping to use the 65 gallon as my main buffer tank which would hold the house/roof wash mixture etc. and then set up my 35 gallon with just chemical to be able to dump portions into the 65. Sorry if this sounds confusing. And pictures or video help would be great. I’m running a cat530 5gpm which I will mainly use with a soft was gun off my reel. Anybody else plum two tanks together and use one for chemical storage and other main tank for wash mixture?

No reason to plumb together …just use your roof pump to transfer. If that sounds off then I am confused on what your trying to do lol.

This is for a roof pump right?

It’s gonna be my main soft wash set up not to be hooked up to a surface cleaner. Basically I was wanting to use one tank as a chemical storage to transfer chemical into the larger tank as needed for mixture. I see a bunch of trailers with a two tanks. One big and one small. Any advice on why? Or is that for two separate pumps? I want to be able to store chlorine in the 35 gallon and then as needed per job just flow some into larger tank then mix with surfactant/ water etc that I will use to wash the house or roof

You shouldn’t upstream chemicals. Two tanks one for water one for chemical.

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They carry 2 tanks because they are separate. The large one is the buffer the machine draws its water from and that the hose fills with water. The small one is the chem tank with the mix made in it. The pressure washer will siphon this chemical down steam via down stream injector. It will mix all together as it’s on it’s way to the final ratio at the end of the gun.

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A buffer tank doesn’t hold chemicals, it holds water for your pressure washer.

Do a lot more reading before buying, building, using anything


Reason said is a lot of pumps are SH safe so I see a lot of people premixing a tank to the correct percentage. I understand there are several ways to do it. And several wrong methods. Just doing research and asking questions since some folks downstream and some don’t

Your pressure washer pump is not sh safe. Sh is corrosive and harmful to your pump. You can premix on something like a 12v softwash system, booster system, or air diaphram. But if you are upstreaming sh through your pressure washer pump you are causing some corrosion in your pump and ultimately shortening its lifespan.


You’ve lost something in translation during your research. As others have mentioned, buffer tanks are for water, not chems. A “buffer” is a device that compensates for a shortage of some sort, or takes up slack. It allows your pressure washer to have enough water on hand even when tap pressure is low.

Chems can be delivered in a number of ways. Downstream injectors are a favorite on this forum for house washing. They inject the chems at a diluted rate down-stream from your pressure washer pump. Generally speaking, they dilute the mix too much for roof cleaning or other substrates that require a “hot mix”.

Then there are low pressure pumps for direct applying a solution. These include 12v, air diaphragm, booster pumps, and probably some others. You would either use a mix tank, or a proportioning system that automatically draws the right mix of water, bleach, and soap from separate tanks.

Hope I haven’t made this even more confusing, lol.