Broken fluval evo?

GHOSTLY · May 25, 2021

So I switched out my pump for a maxi jet 900 but all my chambers for a month were full but all of a sudden the Refugiums is 25 percent filled. Any fix?

SPR1968 · May 28, 2021

I can’t answer the specific question, but I can bump the thread to see if we can get you some help

MaxTremors · May 28, 2021

GHOSTLY said:
So I switched out my pump for a maxi jet 900 but all my chambers for a month were full but all of a sudden the Refugiums is 25 percent filled. Any fix?

I don’t have an evo, but what chamber is the fuge in? Is it just that the new pump is pumping out more? I know in my Nanocube, if I run both return pumps (instead of alternating with a wavemaker), the water level in the tank is higher, which makes the water levels in the return chambers much lower. So if you increased the flow, you may just need to add more water (obviously match the salinity and temp of the tank, you’re adding more volume to the tank, not topping off evaporation).

Edit: After looking at the flow pattern of the EVO (on fluval’s website), I’m 99% sure that’s what’s going on. The design of the back chambers is kind of awful, there are no baffles to keep the water level in the first two chambers, so if the water level is higher in the display, and you didn’t add more water to account for it, the water level in all three back chambers will be lower.

GHOSTLY · May 28, 2021

fuge is chamber 2. I know its not that because I've had it for the past month no problems. Its like its leaking out.

MaxTremors · May 29, 2021

GHOSTLY said:
fuge is chamber 2. I know its not that because I've had it for the past month no problems. Its like its leaking out.

Right, but you said you switched the return pump. If it’s a more powerful pump, the extra water volume its pushing out can raise the water level in the display, so if you didn’t add more water to the system, the back chambers would end up lower. The way the chambers in the Evo are designed is that if the water level is low (either from evaporation, not replacing what you take out in a water change, or the situation I’m describing here), chamber one (the one the display overflows into) will stay around halfway full, and then chamber 2 and 3 will have the same water level (and above the halfway point all three chambers will have the same level). Its a really poorly designed flow pattern, because none of the chambers remain full if the water level drops (in most AIOs, just the return chamber will have a lower water level). If the chambers were leaking, they’d be at the same level as the display (and the display would be lower) because the water would equalize/level out (the pressure in the display is far greater than in the chambers, so if there was a leak, it’s impossible for the chambers to be lower than than the display).

I’m telling you, I’ve owned several AOIs, and have had several larger tanks with overflows, when you increase the power of the return pump, if the overflow isn’t large enough or wide enough to let the increased amount of water being pumped into the tank overflow at the same level as the previous pump, the water level in the display will rise. Usually it’s not much, maybe a quarter or a third of an inch, you may not even notice it, but it’s enough water to leave the chambers in the back of the tank low. Look at the diagram of the filter in the Evo on Fluval’s website, and follow the flow pattern, in order to keep the chambers full, there has to be enough water to fill the display and all three chambers to the top, the baffles don’t overflow into each other, water is allowed to pass through from chamber one to two about hallway up the chamber, and from two to three at about a third of the way up. If the new return pump you put in is more powerful than the previous one (and I’m guessing it is since you changed it), all three chambers would be significantly lower if you didn’t add more water to account for the extra water now being held in the display. Try adding some more water. Worst case scenario, if I’m wrong, is that you have to take some water out.

Edit: if you’re saying that you changed the pump a month ago, have you been topping it off? Is it possible the levels were lower and you just didn’t notice? Because chamber two flows into chamber three at around a third or a quarter of the way up the chamber, so it makes perfect sense that that is where the water level is. Where are the levels of chambers one and three (I’m guessing chamber 3 is as low or lower than chamber 2, and chamber 1 is just slightly higher than chamber 2). Here’s a diagram of the flow pattern: