MP40 tips for 3/4" glass - DMP40 wet side?

reefitup.io · Mar 31, 2026

Setting up a new 200G tank with 19mm (3/4") side glass. Testing out a few different powerheads/wavemakers. Spent the last 2 days trying to get an MP40 to stay on without issues.

New tank just filled over the weekend. Brand new MP40 out of the box. Cleaned glass both inside and out. Using the thin gasket on the dry side as directed in the packaging. Without the zip ties holding up the dry side cable, the dry side will fall during speed changes, feed mode or high speed. Even with the dry side supported via zip ties, I have had the wet side spin freely multiple times, sometimes spinning off and sometimes just spinning in place. I've adjusted/aligned many times. If I keep the speeds very low and constant (< 40%), I can mostly get it to stay put, although I don't trust it at this point.

Has anyone used the suction cup wet sides from the Jebao DMP40 with a MP40 dry?

exnisstech · Mar 31, 2026

I have 4 MP40s on my WB 330.7 that has 3/4" glass and have been running them for a bit over two years and have no issues with them not staying mounted.

PS. Thinking back I did have an issue with a new MP40 wanting to spin. I ran it on low speed for a couple of weeks and it was fine after that. Not sure if something broke in or what. Someone suggested it so I tried and it worked.

get-salty · Mar 31, 2026

i have two mp40s on my WB with 1/2" glass and it is perfectly fine. However, i think 1/2" is the max bc the wet side is a hair loose but no issues.

JP Reef · Mar 31, 2026

I have 2 older MP40's that I use on 3/4" glass. At first they barely held, but after a couple days of running them in green mode then I could shift them to pulsing without the wetside falling off. It just takes some time for the wetside to really stick to the glass.

exnisstech · Mar 31, 2026

get-salty said:
i have two mp40s on my WB with 1/2" glass and it is perfectly fine. However, i think 1/2" is the max bc the wet side is a hair loose but no issues.

get-salty · Mar 31, 2026

exnisstech said:

gotcha.

Good to know.

Boehmtown · Mar 31, 2026

My dmp 40s are maxed at 19mm glass. The back of the tank that has a black film over it makes it too thick. They only work on the sides

reefitup.io · Mar 31, 2026

Copy, thanks. I will let it run for a week or two on lower settings before throwing in the towel.

dazoc · Mar 31, 2026

Another thing that seems silly but can help with the break in, is a double sided tape on the dry side helps with adding some stick until they seat up good. I just bought 2 mp10’s and went from a 60 to a 74 and they wouldn’t stick. Did this and good to go.

reefitup.io · Apr 2, 2026

So, after reading several other threads where people had this same issue, I ended up moving the MP-40 to the back wall of my tank to let it break it in on low speed for a couple weeks. Since the back wall on my tank has some sort of black coating that seemed to have a bit more texture/grip than the plain clean glass, I thought it was a good idea. Only running at like 20-30% constant speeds. Unfortunately that sucker must have started spinning for a while at some point and I now have a nice circle etched into the black back wall finish of my 2 week old tank. Dumb idea, can't say I'm thrilled at the moment.

On a side note, I tested out two of the Jebao/Jecod DMP-55's. With the addition of suction cups, not an ounce of movement OOTB at full power/pulsing/etc. Although my MP-40 may fix itself, I like the suction cups + magnet strategy on the MPD's at the moment.

exnisstech · Apr 2, 2026

That's sounds odd because the film should be on the outside and not leave a mark.

EDIT: The only thing I don't like about the jebao is the suction cups work so well it makes it difficult to get the wet side off for cleaning. Mine is where I have to be careful or coral gets broken. Might not be an issues in a more open tank.

reefitup.io · Apr 2, 2026

exnisstech said:
That's sounds odd because the film should be on the outside and not leave a mark.

EDIT: The only thing I don't like about the jebao is the suction cups work so well it makes it difficult to get the wet side off for cleaning. Mine is where I have to be careful or coral gets broken. Might not be an issues in a more open tank.

That black coating might be an acrylic layer? Not sure. It's an innovative marine 200EXT - so however they get the back walls black, I'm not sure. I tried to clean off the nasty little circle and it's not going anywhere.

ChrisfromBrick · Apr 7, 2026

This is great info. I would only use an MP60 on 19mm glass, and will do so when I get a tank that is in the 180 range.

Rocks reef · Apr 7, 2026

I tried using MP-40s on my tank with 3/4" glass, the wetside just spun slowly. I sold those for two MP-60s which held great but looked like detritus on the sides of my tank. It's a custom Glasscages 48x24x20, so the MP-60s looked huge! I sold those and bought two Tunze Orcas... I am now a HUGE Tunze fan. Mounted them on the back glass, they rotate from side of glass to back of glass... dead silent... lots of cool modes... anyways. Yes, the MP-40s are hit and miss on 3/4" glass. It says they can be used on 3/4" max glass. I guess, that's the greatest thickness they will "hold", operating is a different subject.