RockMongler

It could have just been a small leak of current out of the heater. You can do electrolysis of water (breaking it into hyrogen and oxygen gas) easily with just a 9V battery. Over a few weeks, that could give you a build up of stuff from the water, and give you an effect similar to pearling. Might not be enough to give you a 'shock', but enough to break down the water into its constituent elements, and probably do some scaling with the other ions floating around in the water. I would probably not use that heater anymore.

What I find happens, is the concentrated output is much more obvious in its effect on the tank compared to the diffuse intake with the sponges. The powerhead gives me a fairly distinct counter-clock-wise flow in the tank, though it does distinctly slow down on the front side of the tank, past the sponge intakes. Even if I take the intake sponges off both of the intakes I have, the flow feels very minimal. I just probably need to get some way to better diffuse the flow coming from the powerhead to be more similar to the diffuse intake I have, like making some kind of spreader bar out of PVC. That is what my plumbing looks like under the gravel. 2 intakes drilled with a bunch of extra holes beyond just the top and covered with a large coop intake sponge, combining to feed a single output powerhead. In hindsight, if I were to try this again, I'd probably get 2 smaller powerheads, and do a similar split for both a higher and lower flow area. I'd also probably use something smaller than the 1 inch pvc pipes. Regardless, the fish don't seem to mind it too much (there's still plenty of more chill spots for them, and the minnows will sometimes to hang in the current just for fun occasionally), and over the last few days I've noticed my 4 newer hillstream loaches settling in better and being less spooked by me walking by or the other loach chasing them off. I think the Pseudogastromyzon is finally getting bored of constantly chasing one of the others off 'his' pile of rocks, only to return and find yet another one has moved in and is there. They are getting a proper, peaceful pecking order established from what I can figure. Also, have a short video of the tank.

I just recently upgraded my standard 10 gallon to a 20 wide, with a hillstream manifold. The hillstream manifold doesn't quite work how I'd like (I need to find a better way to spread out the output force, and I'm not entirely sure the entire input of the flow through the powerhead is coming through the intake sponges). I used a hand-drill on the area of the PVC pipe the sponges cover to get a greater intake across the whole body of the sponge, rather than just at the tip. There still is quite a bit of swirling action rather than full on directional flow, but it was still a fun project to build my own streamflow manifold. I'd definitely get a smaller powerhead than the aquaclear 50 I have running it now. I also have aquaclear 30 HoB for that extra touch of filtration (and for helping deal with fines better than the sponges) I have white cloud mountain minnows (and they have been sucessfully breeding, as you can see by the distincly blue striped jeuvenile) I also have 2 species of hillstream loach. I think the reticulated one is a pseudogastromyzon cheni (or myersi). I only have one of those, the other one I purchased at the same time didn't make it. It was a bad shipment from a LFS I go to in Houston, and the other dozen loaches didn't make it overnight. I got there the next day, and the one that is still alive is kind of the ruler of the tank. He definitely is dominant over the other loaches despite being slightly smaller. The other hillstream loaches I have, I have some of the Beaufortia kweichowensis I purchased from aquahuna. I suspect there might be multiple species, as one of them definitely prefers resting on the substrate, and the others prefer the vertical glass when they are hiding, but from what I can tell looking around the internet, the hillstream loaches aren't as well studied as we might like. The substrate is pea gravel from Lowes, and the larger rocks are either collected locally in East Texas (the orange sandstone), or I gathered them on a previous trip to Colorado (pretty much everything else). I'm currently treating the tank with seachem flourish to handle the staghorn/black beard algae, along with playing around a bit with my lighting. Still, the fish seem more active in the 20 gallon, so overall I'd call it a success. It is a pleasure to sit down and watch at the end of the day.

There are certainly various ion sensors out there for things like pH, kH, gH, NH3, NO2 and NO3, but, in my experience, they are finicky and require regular calibration. I've mostly worked with digital pH sensors, and the sensor has to be kept in a special salt solution when not in use. If they aren't kept in the special salt solution most of the time, the accuracy of the sensor starts going down because the ions inside the sensor can leach into the water being sampled, and eventually cause the sensor to become non-functional. Good digital sensors for detecting water parameters do exist as well, they are just not for the layman. They also aren't designed for 24/7 operation. The brand of digital sensors (Vernier) I use in my classroom has ion-selective probes that can look at Nitrates, ammonia, and various other ions in solution, and the probe runs ~$250 (new with amplifier), and require constant calibration, and the actual detector is very time limited, so you might have to replace the detector electrode somewhat often (at a cost of ~$80 for a replacement electrode). You also can't leave it running all the time, because it needs calibration, and leaving it immersed in water for long periods of time causes the electrode sensor to degrade more quickly from what I read in the instructions. Even their pH meters, which are cheaper, still would rapidly degrade in an aquarium environment. Getting a set of them for sampling water in a fish room, or from a single tank would be cool, but you would be looking at upwards of $1000 for a full suite of sensors (pH, Nitrate, Ammonium, I don't see many specifically for nitrite), along with having to replace stuff over time as the sensors degrade. I'm not familiar enough with their design to guess if they could be adapted to a constant reading situation like we would want for a fish tank, but I assume it's probably a bit tricky. However, for those of you who might have issues with colorblindness, these kind of tests might very well be worth the investment for general periodic testing if you are into gadgets and stuff (and are willing to drop the cash).