inert/ stable dye for storage h2o?

[pybyr]

Hello all-- I've been back at working on completion of my storage- the big (unpressurized) tank now has four sides (plus a floor) sealed together and a 75 ft coil attachd within it for DHW (connection to the boiler will be by way of a flat plate exchanger). Cover and insulation go on fairly soon.

I've got a 1" overflow port near the top of one of the tank sides, and a drain port at the bottom. I am planning to use a vertical piece of un-colored PEX tubing (tee-ed in at the drain port and running upward) as a "sight glass" to be able to see how full the tank is without having to open the top access hatch that'll be hard to get to.

My father made the excellent suggestion that if I can find some sort of dye to put in the water in the tank (and that won't react with the tank or plumbing) (409 stainless tank, , it will (1) make the 'sight glass' much easier to read; and (2) serve as a way of 'spotting' leaks if any ever occur -- if I see some liquid (and this is an old farmhouse cellar, where moisture has been known to appear at various times from various sources) by confirming whether moisture has really come out of the tank vs. some other source.

Does anyone have any suggestions on some low-cost dye that won't react in some adverse way with 409 stainless steel (and bronze circulators)? For that matter, anyone have any suggestions of products to avoid? I am thinking that perhaps food coloring might be a good way to go?

While I'm on the topic of water treatment/ chemistry, here's another question-- the tank's panels are made from 409 stainless, fabricated for me by a company that focuses on providing bolt-together stainless tanks for industrial, municipal & agricultural purposes. Based on their use of the 409 alloy for other tanks (much larger than mine) they've indicated that the stainless will definitely form some degree of surface oxide coat that may discolor it, but that it will not corrode in any way that affects its water-tightness or structural integrity. But- when thinking about the dye, I got to wondering whether it might be possible or desirable to add something that will cause that surface-reacted layer to form quickly/ evenly (such as is sometimes achieved with various metal-finishing processes). Anyone with some depth in chemistry have any suggestions (or for that matter, reasons to not go in such a direction)?

Thanks

 

[DaveBP]

Trevor, how about putting a float ball in the tube? Something quite loose in the ID so it won't get stuck but large enough to not go through the fittings at the top and bottom? The water in the tube itself should be ambient temp so nothing exotic would be required.

 

[pybyr]

Trevor, how about putting a float ball in the tube? Something quite loose in the ID so it won't get stuck but large enough to not go through the fittings at the top and bottom? The water in the tube itself should be ambient temp so nothing exotic would be required.

Great suggestion- and one that I should've thought of, since I set up exactly that type of float-ball indicator for a friend's maple sap tank (for those outside maple-producing areas, the sap is used to make maple syrup). In that case we used a fairly large diameter clear PVC tube with a ping-pong ball for the float. I'll have to look into what's available for a small, visible float ball that'd fit in my planned PEX sight glass- and/ or look for some clear tubing that isn't too expensive.

 

[Sting]

You won't need to dye or otherwise color the water that you view in the sight glass. You may more value a way to clean it so you can see the liquid after some time in use.