DIY Softwash Metering System


I’m no expert on the best size for the soap lines, but i would agree with Alex that the amount of soap used is usually far less than the other parts of the solution, so whatever valve you use needs to be able to accurately deal with comparatively small amounts passing through it. So a 1/2" or even 3/8" valve might be better than a 1"… again… uneducated guess here. If a 1" valve can portion it out correctly and easily, then i guess it doesn’t matter.

Also, i would suggest maybe just focusing on a 3 valve solution for now, for simplicity’s sake, to get a base model. After that, one could look into how adding more valves would work.

Just curious, is there a big price difference between 3/4" and 1"? I would think that even 3/4" would be a big improvement over 1/2", but if there isnt a huge difference in price, and there was no loss in performance from going as large as 1", then i guess it wouldn’t matter.

Here’s a photo someone posted on a Facebook discussion about larger sized metering valves. Dont think you have posted these, but not sure.


Thanks much! I really appreciate the suggestions. I have looked at the Plastomatic metering valves a lot and the reason I haven’t brought them up on this thread is that I don’t think they are a good solution. They only offer a 90 degree rotation, which means 1/2 the resolution and accuracy you could have with a valve that rotates a full 180 degrees. Therefore, I’ve limited the options to valves that have 180 degrees of rotation only. And I can only find 2 models and manufacturers lol. There might be more, but I’ve searched for hours and hours and haven’t found anything else.

The Hayward true union ball check valves would work I think too, but they are huge. I think the outer diameter at the union is 2.5-3" for the 1" check valve. That’s huge. I’d really like to find an inline option in the correct sizes and in PVC, not polypro, and with no metal internals or Hastelloy internals. I’m having major trouble locating the right part. I’ve got emails out to several manufacturers to see if they offer the right part or can make it, but I haven’t heard back yet.

I appreciate the suggestion to focus on a 3-to-1 option first. That’s probably better. I get so excited and start thinking pretty far down the road lol. It really bothers my wife.

As far as metering valve pricing, I’ve requested a quote on the GF 523 3/8" and 1/2" and also the Chemline 1/2", 3/4", and 1" 180 degree metering ball valves, so I’ll know the price for all the options that I believe are viable solutions.

The next step is to identify the BEST option for check valves. I think this will be pretty difficult. Then see about having a special manifold made that doesn’t have flow restrictions and minimizes the required fittings.

In regards to flow, I was doing a little reading and learned that engine exhaust doesn’t like 90 degree turns and high flow exhaust manifolds eliminate that. Here’s a picture. This is what I’d like to accomplish with a custom designed double wye or blend manifold.


I just found this thread and it’s been very exciting. I too started researching building my own mixing setup. I found a GF distributor that’s local to me and they priced the 523 metering valve for me around $85 so you beat me on the price you’re getting. You will have to let me know if you can hook me up on them. I ended up only picking up some 1-1/4" x 8’ square bar to have milled for my manifold and a stick of Class 120 1/2" pipe since I was strapped for funds at the time but I’m getting closer to getting it made up. I don’t think it’s going to get any better than the 1/2" polypropylene check valve with the Hastelloy spring but I only researched it a “few nights” lol I want to say Kleen-Rite had the best price on it and they are local too.

Good work though bro, my name is Dez btw

I was finally able to get my softwash wand threaded with a tap and die though so I have made progress. This wand is 24" but I went ahead and cut up a 30", 36", 42" and a 48"


I had a discussion with one of our mechanical engineers. I learned some things and went through a fluid flow analysis on the metering manifolds and I have some interesting information to share.

With 1/2" plumbing and 2 90 degree elbows per line (manifold made from standard PVC fittings) like the one I shared originally, and probably what others are using, that system will have 11.44 PSI of loss and the head of the pump. If you make an identical system with 1" fittings, it will have .82 PSI of loss at the head of the pump. These figures assume 25 feet of pluming at either 1/2" or 1" and 2 90 degree elbows. I used 25 because I figured that’s about what someone might have from the buffer tank, through the manifold, then to the 12V pump. As you can see, there is a large difference. This loss is transferred through the pump and effects final reach of a softwash system, at least from my understanding so far. Obviously this would need to be confirmed, but it does make sense, to me anyway. If you disagree, please tell me and explain why. I’d love to know.

See headloss calculations below:

1/2" Headloss

1" Headloss

So it sounds like a custom manifold with high flow curves might not be necessary, but I’m having it quoted anyways for comparison. Once that is priced, I may have some changes made to it to make it more compact, but it may be too expensive anyway. After all, the whole point is to do this economically. But, a one piece manifold has less fittings to order and assemble and less joints for potential leaks. This means that even if there is no flow benefit of a one piece manifold over standard fittings (assuming 1"), there would be an application advantage to having the one piece manifold. So if cost isn’t too bad, that might be the way to go.

See below for one piece high flow manifold concept.

If you have comments, feedback, or suggestions, please let me know!


I still think 5/8 or 3/4 for soap and SH intake more than enough for 12V systems. At the pump you only have 1/2’ intake or 3/4 depending on fitting used and even FB at 85 psi will only pump about 5.5 gpm. I like the simplicity of the one you showed above, the softwash metering kit. With slightly bigger fittings, the 90’s don’t bother me as much, especially on the intake side.


Boy, you beat me to the punch. I was just about to suggest that the 90° turns should have much less impact when using larger plumbing.


I still want to have a machine shop mill the GF 1-1/4" square bar I purchased to make my manifold but in the past when I thought about making a manifold myself I wanted to use two wye’s “stacked”. They would, of course, lay horizontal and the “bottom” would be the outlet and the top would be the water inlet. Maybe that idea will help your creative juices???


Ive considered tgat, but then you end up with plumbing coming vertically in the too at a weird angle, which means your valves visually will look off instead of square. Then the outlet Syed would also be at a strange angle. The OCD in me wants things parallel and or square with each other lol. But you are right, I believe that would also work.


I got a final drawing back from the PVC manufacture for a custom one piece manifold design. Don’t have a price yet, but I thought I’d share the concept and ask for opinions.

My question is about space and aesthetics. It looks cool, but the manifold itself is 10" long. Add to this a check valve and metering ball valve on each inlet line and a filter on the outlet and it’s a pretty tall setup. What do you guys think of it? I appreciate your feedback a lot!

Also, since there isn’t much PSI loss through the 90 degree version with 1" pipe, and it’s much more compact, I plan on having a one piece design of that concept quoted as well. Will update. Please comment or give your thoughts!



Did you guys know that Delavan recommends placing a 50 mesh filter inline on the inlet side of the pump? My mechanical engineer says that without filtering as the manufacturer recommends, small particles and debris can get in the pump and as it goes through the diaphragms, they will scratch at the material and will eventually cause the pump to seep water and lose pressure on the outlet side. It then needs to be rebuilt or replaced.

I found a perfect y strainer that could be installed on the outlet side of the manifold so it’ll filter everything at one time before pulling it through the pump. It’s clear PVC and has a PVC mesh strainer so that there is still no chance of any corrosion happening. The mesh filter is also bright orange and looks pretty cool. The clear PVC allows the operator to visually see fluid being pulled through and also check if the filter is dirty or not. Here’s what it looks like:



I like the see through filters…expensive but i like them


It’s actually one of the only ones I could find that has a PVC option for the mesh screen. Nearly everything available is only stainless steel mesh. I’m not sure how much the cost of this will be, but I think it’d be good to make it part of the system. I think it’s something that SHOULD be there, even if other systems aren’t making it part of theirs. I guess once I get the price, it could always be removed from the parts list if it’s too much, or offered as an option to people who wanted to filter their lines to extend the life of their pumps maybe.


I like the clear PVC Y strainer you found, I have not stumbled across that one. I use 1" schedule 80 drop tubes that are capped on the bottom and extremely thin 1/32" slits in it for filtering. I blow back on the system every once in a blue moon to clear it. It’s always spotless in my tanks but I filter just cause. My tanks are sealed and vented though so that may be why they stay so clean


Those strainer comes with 20 mesh which is 1/32 hole sizes. But Delavan recommends 50 mesh. I’ll replace the filter with a 1/64 hole size PVC mesh that is basically 50 mesh. As close as you can get with PVC. This will perfectly protect anyone’s pump downstream of the metering system.


I 've had one of these for 3 years for my drop-in hose. Works like a champ.


Is it threaded? I cant tell in the photo.


yes female - Same one Bob uses on his 12v systems too


You mean the PressureTek guy? And by using them on his 12V systems, do you mean attached to the end of the drop sticks? Easier to view them on the PressureTek website. I haven’t seen them before. Just for anyone else who might be wondering.




Thank you. Do you think that’s better than having a strainer on the manifold? It’s obviously cheaper for sure. I appreciate your advice. :slight_smile: