You're running Ebb/Flow IIRC? Nice looking babies
Yeah, the difference in reliability and even cost, is really fairly minimal between using a water pump or not. The only real reason not to use one is heat in the rez. In a smallish rez, a submersible pump could add significant heat.
Ive been thinking about the differences between the various types of hydro and it all comes down to the ratio between water and air to the roots.
On one end of the scale, you have DWC, water farms, and hempy buckets. They all have a significant % of the roots in water full time.
Next is Ebb/Flow, which in some cases also has a portion of the roots wet 100% of the time, but most seem to drain 100% from what I have read. Ive seen some people who flood a lot and some who only do it 4 times a day, so there is a wide range here.
Next would be the various NFT setups and low pressure aero. Again some of them flow a lot of water and some very little, so how 'wet' the roots are varies a lot.
The highest ratio of air to water looks to me to be the membrane meniscus setup, but I guess the fogger/mist type hi pressure aero systems would be pretty close.
My point being that all of these systems can produce excellent results - if done correctly. I actually dont expect to see a huge difference between the three techniques Im going to try, but it will be fun and interesting to see how it works out.