I’m watching “unbiased” reviews about the riptide on you tube right now, and some of them are hilarious. Like some of the complaints are almost common since. “Don’t pull the air release because it’s a burn hazard”. I will have to look into drain back with this pump
I haven't used every pump there is, but I have to believe there's drain back with most if not all of them.
Here's a pic showing my setup, more or less. Still working on optimal hose lengths and positioning and such.
The pump has to be below the level of the kettle, mash tun, whatever, so that is filled with liquid. The Riptide has the pressure release to assist in priming the pump; if the liquid is boiling, you need to be careful of that. The alternative is having to futz around w/ the hoses.
Now, imagine I'm racking strike water from the kettle on the right to the mash tun on the left. I have to feed that from the kettle into the pump, and from the pump into the mash tun. The pump has to be lower; once the kettle runs dry and no more water is feeding the pump, then what?
The pressure from 10 gallons of mash in the mash tun will try to push that liquid back through the pump and back up into the boil kettle, which obviously I don't want.
I can deal with this in two ways; when the pump runs dry, I can close the ball valve to the mash tun, but that still leaves me with liquid in the hose. I'll clamp the pump-side of the hose, disconnect from the ball valve, then dump that into the top of the mash tun. I know it's not a lot, but I'm working to limit losses as I go through this, and with a pumping system, there are losses.
So that's all I'm doing there.
The other way is to find a way to push that last liquid into the mash tun. I've been experimenting w/ using CO2 hooked up to the inlet hose into the pump to drive the remainder of that liquid through and into the mash tun, where I then close the ball valve.
That's a work in progress; if I'm not careful, or have too much CO2 pressure, I can get an interesting result in the mash tun.
********
There isn't a pump here that people haven't had success using. I like the Riptide because it has the integral valve, pressure release, it's very quiet, long cord, on/off switch on the unit, splash-proof, but you pay for that, though by the time you add things to the cheaper pumps, the price difference isn't as apparent.
As I watch you try to resolve this problem, I think you're overthinking it. All of these work; it's only a matter of features and price that should be guiding you, and only you can decide which matter most.
Anyway, good luck.