• 29.05.2024, 16:54
  • Register
  • Login
  • You are not logged in.



Junior Member

New D5 Next Pump noisy over 4400RPM

Thursday, March 14th 2024, 7:38pm


Recently I've bought an D5 Next + Ultitube + Leakshield combo and after fitting everything there is a problem with the pump.
All working fine up to 80% of power, which is around 4400RPM. Above that there is some kind of grinding noise coming out of the pump.
I did not take apart the assembly, except Leaksield from the top to take out rubber tube fitting from the inside. There is no air bubbles left in the system, no leaks.

Any advices regarding the issue? Is the pump faulty?

D5 Next Noise.mp4

Saturday, March 16th 2024, 1:50am

Curious to see what others think about this but If no air bubbles or air pockets remain then that doesn't sound good to me.

However, I suggest you send this video clip directly to Aquacomputer (skip us middlemen) and let them direct you on what to do.
"Never be afraid to try something new. Remember, amateurs built the Ark, professionals built the Titanic"

Saturday, March 16th 2024, 7:49am

It sounds as if there is still air in the pump:

a: the rotor of the pump can wobble if air is present
b: something has come loose in the system and is hanging in the pump bearing

Which coolant was used?


Junior Member

Saturday, March 16th 2024, 11:18pm

I'm using EK-CryoFuel.
Tried to to deareate many times with Leakshield and that gives exactly zero difference. No visible air bubbles anywhere.
There were some bubbles on first run for a short while, but thats it.
I'm using 2x 360 rads and CPU/GPU blocks in the loop if that makes any difference. Got a bit over 1l of coolant in system. No overheating anywhere on full load, max water temp 34°C, no noises under 4400RPM.

I can empty and refill system for a test if needed, but do not have any other coolant in hand. Can use distilled water, which I was successfully used with old setup in last few years. Can even put old pump for a test as I guess all D5 pumps got same top fittings.

As stated in 1st post I did not touch pump fitting, was factory fitted, so there should be no hanging objects in bearing.

This post has been edited 1 times, last edit by "darrecky" (Mar 16th 2024, 11:25pm)

Sunday, March 17th 2024, 10:20am

I'm using EK-CryoFuel.
Which one exactly?


Junior Member

Sunday, March 17th 2024, 6:24pm

I'm using EK-CryoFuel.
Which one exactly?
Mystic Fog

I've drained and refill system twice with current pump. Same behaviour.
3rd time replaced the pump with old one and I have no weird noises 1st time.

I can hear an air bubble going through pump from time to time (lot of air in system due to experiments), but this is completely different sound than that grinding noise from other pump.

This post has been edited 1 times, last edit by "darrecky" (Mar 17th 2024, 6:29pm)

Monday, March 18th 2024, 7:31am

Mystic Fog

This is not suitable for water cooling.
This will destroy the pump bearing. This is intended purely for show purposes, not for prolonged use.
Contact support, I assume that the rotor or the bearing that runs on the ceramic ball has been destroyed.


Junior Member

Tuesday, March 19th 2024, 8:45pm

Can you please share the source of your opinion please? I've been using it over the year before and old pump (EK PWM) is still going ok - no problems at all. Decided to do some improvements due to components changes and new pump made those noises straight from the box.
I couldn't find anything wrong about that coolant before I bought it at 1st place so it is a little hard to belive to be honest


Senior Member

Wednesday, March 20th 2024, 5:31am

I have never (and would never) put Mystic Fog in my loop. I have read countless horror stories about that stuff – mainly the particulate falling out of suspension and clogging up the cooling fins in blocks and staining everything it touches. Go look on the r/Watercooling Reddit and you will find many posts from people who had to tear down and clean out their entire loop after using Mystic Fog. It also contains sodium 2-ethylhexanoate, so it’s probably highly conductive like regular Cryofuel is. EK does not list conductivity for Mystic Fog, but for Cryofuel, their spec says 1.4mS/cm. EK stated that it’s actually even higher, about 2.2mS/cm fresh out of the bottle. Note that the conductivity is stated in milli-Siemens per centimeter. The conductivity drops from ~2.2mS/cm to ~1.4mS/cm as the sodium 2-ethylhexanoate reacts with metals in the loop. It’s interesting that the very first feature EK lists is “low electrical conductivity” while their spec has this crazy high number.

Aquacomputer DP Ultra has a very low conductivity. Out of the bottle it's around 5 to 10uS/cm (micro-Siemens per centimeter, which in milli-Siemens per centimeter is 0.005 mS/cm to 0.100 mS/cm) . The conductivity of DP Ultra increases over time. Aquacomputer recommends replacing it when the conductivity exceeds 100uS/cm (0.1mS/cm). Fresh Cryofuel’s conductivity is 22 times higher than what Aquacomputer considers safe to use. Highly conductive fluid can provide a path for current to flow, which can promote corrosion. It can also do a lot more damage if it gets on a live circuit. This is the main reason I would never put this stuff in my loop. It’s also quite toxic and a skin irritant. I don’t know how long it would take to destroy the internal parts of a pump, or if that is what caused the noise you are hearing. If it made that noise right away, I doubt that the Mystic Fog destroyed it (yet). Maybe if you thoroughly clean that stuff out of your pump it will stop making the noise.

Wednesday, March 20th 2024, 6:39pm

EK itself states on the Mystic Fog product page that it is recommended to change it every 6 months "For the best light dispersion effects of EK-CryoFuel Mystic Fog, it's recommended to replace the coolant every 6 months. "

The safety data sheet then states: "Changing the coolant is strongly suggested at least every 6 months. "

I think this should make it clear that even EK does not consider it suitable for long-term use

Translated with DeepL.com (free version)
Es gibt keinen Ausweg, den ein Mensch nicht beschreitet, um die tatsächliche Arbeit des Denkens zu vermeiden.
Thomas Alva Edison (1847-1931), amerik. Erfinder


Senior Member

Saturday, March 23rd 2024, 2:15pm

opaque coolants, even those that advertise no "redeposition" do end up making clumps of particles everywhere. in fittings, in rads, in blocks...
And since the ceramic bearing of the pumps is water lubricated, you basically end up adding slightly abrasive slurry in the water.
long term damages aside, if you want to go back to clear coolant, it's a nightmare ^^'
I used an opaque coolant once for 3 weeks, and have had cloudiness in my loop for the following two years despite numerous flushes, complete teardowns and manual scrubbings etc...

When i compare the rotor of my D5 and DDC, it's easy to see which one ran opaque. the D5 has lost all the plastic sheen on the rotor, yet the DDC has more run hours on clear coolants.


Junior Member

Saturday, March 23rd 2024, 5:34pm

I would love to buy aquacomputer coolant, but in UK supply is very limited. 2 UK stores are selling their stuff, but no coolants there. Most stuff is pre order, simply aquacomputer stuff is very rare. In the other hand EK is available everywhere.

I've read stories about issues with other opaque EK coolants, but not mystic fog. And they were related to coolant contamination. As stated before, so far mine were faultless, but I haven't done any inspection between coolant replacements so it might not be as great I might think.


Senior Member

Sunday, March 24th 2024, 9:01pm

I suggest you dump the Mystic Fog, flush the loop with distilled water, dump it and flush again until it stays clear, then see if the pump noise stops. You may have to disassemble the loop and clean any gunk out of the CPU and GPU blocks. Regarding the pump, it may be gunked up or it may actually be a defective pump. You could disassemble the pump and see what’s going on in there but if I were you, I would do as Sebastian from Aquacomputer suggested and contact support first. You don’t want to void whatever warranty you have by taking it apart unless directed. Contact them and see what your options are.

DP Ultra – Watercolling UK has 1 liter clear and Red in stock and all 6 colors in 5 liter jugs. It is also available from Aquatuning and the Aquacomputer Online Shop. Good luck!

Monday, March 25th 2024, 8:53pm

Darrecky, I have never used any of that pretty stuff in any of my water cooled systems. I even stay away from colored fluids. I simply use distilled water and Mayhem XT1 Nuke (10%). I try to keep it simple. I use this setup in both of my built PCs using AQ's water pumps (3x), including the Ultitube and have had no issues. I suggest trying distilled water and some sort of additive since you can't get their product. Just One Man's Opinion.

Let the community know the disposition of this issue.
"Never be afraid to try something new. Remember, amateurs built the Ark, professionals built the Titanic"

Wednesday, April 24th 2024, 9:11am

I have the same issue with my D5 pump, which only runs with the clear DP Ultra fluid. In the case of air bubbles under the rotor, how does one fix this?


Thursday, April 25th 2024, 1:36pm

In the case of air bubbles under the rotor, how does one fix this?
run the pump for several days at different speeds.
sometimes particles from the water loop can also be the cause.

Monday, April 29th 2024, 4:34pm

In the case of air bubbles under the rotor, how does one fix this?
run the pump for several days at different speeds.
sometimes particles from the water loop can also be the cause.
Thanks, I've done this and the sound is gone now :)

Sunday, May 12th 2024, 7:11pm

OP, any updates?
"Never be afraid to try something new. Remember, amateurs built the Ark, professionals built the Titanic"