Worth every penny. Big scale. Sharp optics. Not temperamental.
The thing is, most people wouldn't dare spend that much due to most refractometers being priced substantially lower. Inaccurate salinity is probably a much bigger undiagnosed problem in this hobby than most people be willing to bet on. I had three refractometers give me wildly different results even when calibrated.
Low pH is ubiquitous in this hobby. You'll find that people are obsessing over pH now-a-days, because stable alkalinity has been for the most part been solved with the help of this forum, proper equipment/ products available, and Randy's articles. So we need something else to obsess over. Stable (or even low variability) pH is just that next beast to conquer and I think the last frontier for the basic major inorganic chemistry we have to tackle.
People say don't worry about it, but it's something that can be solved or lessen in its impact. There's no reason to just accept it if you can do a few simple things like running an airline outside. Every bit can help.
As for cleaning sand, I do not, because its just another cofounding variable to address. Sand is something I am thinking about eliminating totally to see if it's a contributing part of the problem. I do not want to disturb the micro-biome. I do have a very shallow >1 inch sanded.
The pH never stays stuck, but what does happen is the diurnal shift down, which is when the algae in the tank no-longer is performing photosynethic respiration. Light on - pH shoots up. CO2 is consumed.
I do like your thoughts on this.. That's going to be more difficult to monitor, but now that we have automatic testing systems, it's possible. Probes, would be extremely costly.
I would like Randy to expand on his reasoning for my understanding, which I think I understand what he's saying there. If anything, the buffer from amines would help this situation? CO2 is the main enemy because its the chief by-product of most of everything in the tank. Right?
I know it seems hard to accept at first, but once I performed the aeration test OUTSIDE, which is driving off the excess CO2 that's in solution of the tank water, the pH goes up. Its thought (more or less a fact at this point) that CO2 concentrations are higher inside, than they are outside. Taking the same test, but doing it INSIDE, pushes the pH down.
It's a simple test that I did as a teenage in chemistry class with a pH indicator in a cup of water, blowing into the water with a straw, the pH indicator turns GREEN when the solution's pH is around 6.0. CO2 decreases the pH of the water going into solution. We all breath it out -- CO2, and its in our homes, and sucked into our aquariums with our skimmer.
Look at this signature with this table. It's a predictive value of Alkalinity CO2 concentration and pH.
So my theory is using OUTSIDE air in a skimmer, can make an impact -- ONLY IF the volume of air being drawn in, can overcome the tank gas exchange of the surface of the water, and the concentration of CO2 that's in that indoor environment. So in my example, I am using a skimmer that's rated (which ratings can be ambiguous or arbitrary) 5x times the rated size for my tank to receive only as of right now, 0.1 average daily influence in my pH.
This is also a reason why CO2 Scrubbers may not work for some people due to the amount of air-draw volume being too little for their environment and size of the tank. An undersized skimmer may not have the power to run it properly.
obvious positive effect but difficult in an 28 gallon all-in-one
