I looked at mine a year down the line and nothing!.
I did dose kalk slurry heavily for a week or so a few months ago and managed to seize one of the pumps. It was caked in deposits, that disappeared quickly with a vinegar bath.
What are the skimmer pumps you are trying?.
Thanks
Mo
We are trying the Abyzz 420 needle wheel. The 215 may be strong enough, and it is a very similar pump, but with the added head pressure and minor cost difference, we decided the 400 w model was a better choice.
Our RK2 came with a low pressure pump for the 1.5" Mazzei injector venturi. We upgraded to a Panworld/Blueline 70HD pressure pump and performance was greatly improved, but we still have a long way to go in the performance department.
One feature I would like to add is flow control via the Venotec ACS controller. I would like to surge wet foam for a few minutes every hour. This will remove stubborn hydrophilic carbon, clean the skimmer neck, perform a minor water change if I turn it on long enough, and coax the RK2 out of its frequent "on strike" mode. When the RK2 internal neck wash comes on for a minute, the skimmer resumes skimming for a few minutes, then slacks off again as if it's on standby. The other solution for this problem is to increase the volume of air entering the skimmer. This is a pre-bubbleplate skimmer with a large contact tube. The body of the skimmer is about 5' high and 14" wide and it isn't transparent so we have no idea what is going on inside. It expels a lot of stray bubbles in the effluent which makes a mess in our pst skimmer refugium. We have three 7" x 16" 100 micron filter socks, three 300 micron media bags, and a set of dam & weir bubble traps on the effluent and it still makes a mess.
One method of increasing air volume is to get a bigger pump for the venturi, such as a Blueline 100HD. These are noisy, energy hogs, vibrate, and the increased velocity will probably give us more stray bubbles in the effluent. A better solution is a DC needle wheel pump. It can generate lots of bubbles with limited velocity compared to the outmoded venturi valve. It will accomplish this silently with no vibration, and minimum energy consumption, but the main benefit is the control options. We can govern air production via air intake line valve as well as the RPM of the pump itself. The throughput pump can vary the water level in the skimmer and the needle wheel pump has the potential as well. Of course the skimmer came with a stock gate valve but it requires manual adjustment, while the DC pumps can go through wet and dry skimming modes on a timer. Which brings us to the other feature we are trying to implement, minimized night skimming.
We would like to experiment with reduced skimming at night. Right now it isn't a big issue because we aren't skimming much, but once we tune the RK2 up to a respectable piece of equipment we may have to back it off periodically. Night time is the best time to do this because this is when plankton are actively swimming around and when corals have their feeding tentacles fully extended. Free floating bacterial populations are greatly diminished by skimming so a nightly cut back in skimming will allow these populations to replenish.
We are trying to strike a balance between highly mechanized water polishing and disinfection (ozonation) and biological assimilation and dissimilation through bacteria and other living organisms. Too much of the former greatly diminishes the latter. One way of approaching the issue is to use an inefficient skimmer so it can't over-skim. The problem with this is it will likely under-skim. We want to harness the power of the skimmer and have it work hard when we want it too (during the day during nutrient import), and back off at night (during natural feeding and biological filtration). We can dial our newly tuned skimmer down to our current performance rates, and turn it up to 11 during the day with DC pump control. If there is a spawning event or some kind of die off during the night, the skimmer is still there to pick up the slack. Turning the pump off at night doesn't give you that option and you will always worry that the NW pump will not turn the right way or come on with most pumps on the market.
If I really want to roll up my sleeves I could build a bubble trap and insert it in the RK2, but it's a very small area to work in and there's no easy way of affixing it into the body. The obvious question is, why not just swap the whole thing out for a Bubbleking? It's cheaper, plug & play, quiet, vibration free, energy efficient, a fraction of the size, reliable, and guaranteed to do exactly what it is supposed to do... well... Peter had the skimmer already, and it's just about the only thing left from his initial (very large) investment. The skimmer cost more than all of the other equipment put together, so it has to work, and it will
.
