Scratches on Aquaclear Motor Shaft With Sand Substrate

The motor shaft in my Aquaclear 110 lasts about one year before the shaft gets scored to the point where the motor rattles fairly loudly. I replace the shaft, and am good for approximately another year. Is this shaft replacement cycle typical for Aquaclear filters?

The filter is in a 29 gallon tall tank with a pool sand substrate. I have a Filter-Max III pre-filter on the intake, and the intake is 3.5" above the sand. I put a dinner plate on the sand substrate when adding water during water changes, I also leave the filter powered off for one hour after a water change to allow any sand that may be suspended in the water to settle back to the bottom. Occasionally there is a small amount of sand in the filter box, but it is just a trace. The tank has emerald cory cats and platies.

Any ideas on whether this amount of wear is typical would be appreciated.

 

Any wear isnt typical in an aquaclear. Im still running a 500 on my 75 gallon. Its around 18 years old and the only thing I have replaced is the lid because I stepped on it. You could try putting the intake higher or a prefilter sponge on it.

 

I have the Filter-Max III pre-filter by Aquarium Technology on the filter intake now. This is a 29 gallon aquarium that is 18.5" tall. I do use an extension to push the bottom of the intake down to 3.5" inches above the substrate. I thought 3.5" would be enough distance to prevent sand from getting into the filter. It seems sand substrate will require replacing the motor shaft as part of normal maintenance.

 

I don't know. I have sand in my tanks and my Aquaclear shafts aren't damaged, nor have I ever found sand in the impeller or media basket chambers. You may want to try a finer prefilter.

 

JenC - thanks for the advice. Is your intake approximately 3.5" away from the sand like mine is?

 

JenC - thanks for the advice. Is your intake approximately 3.5" away from the sand like mine is?

3-3.5 inches from the bottom of my pre-filters to the sand, yes.

Your sand may be finer than mine and/or your pre-filter may be coarser sponge. Some people don't use pre-filters though, and sand still doesn't get sucked up. I'm curious how all that sand is getting in there.

 

It is never a lot of sand. I find just a trace of it, but it must be enough to damage the motor shaft. I'm just going to live with the yearly motor shaft replacement routine.

I viewed a few YouTube videos, and according to those authors, the shaft is a wear item due to the rotating of the impeller, so a replacement shaft will be needed periodically.

 

I have replaced my Aquaclar 110 impeller shaft with the ceramic impeller shaft of a Fluval 406. It's supposed to last a lot longer.

Just be careful you don't snap it, because getting out a snapped impeller shaft is a huge PITA.

 

I think Ive bought 2 or 3 shafts for my assorted AC's over the last couple of years for the same reason. They use the same prefilter as you have.

By the way, you have an AC110 on a 29g ?

 

First a couple things must be clarified.
The shaft is the bright metal (stainless steel) rod that is inserted into the motor. The rotor (gray magnet) and impeller surrounds and spins on the shaft. The rotor and impeller can be pulled up and off with the shaft still inserted into the motor.
So is the shaft getting scratched or the rotor? I cannot see how the shaft can get scratched as it is inside the rotor and not exposed to any elements including sand.

Unlike many here, I have had lots of hard lessons regarding sand and AC filters. I have burned up two motors in 3 years. Should the rotor/impeller get stopped with power applied to the motor, it will destroy the motor. Sand intrusion will stop the rotor from turning.

I do not use pre-filters as they are messy (removing them can dump all the contents back into the tank).
My issue was agitating sand while the filters were running. I am now shutting off the filters before I start doing maintenance. It only takes a few grains of sand to stop the rotor/impeller from turning. You will hear it when this happens. You will hear the sand scrubbing the stator housing.
Pre-filters work well for this, but I remove them immediately after I am done with water changes and cleanings. (Maintenance).

Question. Why are you replacing what I now believe is the rotor because it is scratched? Scratched rotors should not make any more noise than one that is brand new. Pristine.
And lets be perfectly clear.
The motor consists of four parts.
1) The stator. This is inside the motor housing and cannot be seen.
2) Then you have the stainless steel shaft. It is inserted into the motor with firm pressure and should be checked. If the shaft is not fully seated into the motor it will result in noisy filter operation.
3) The rotor. This is the cylindrical magnet that slides over the SS shaft and where you position the impeller onto. This part should never need to be replaced. It is a permanent magnet and unless it somehow has become compromised.
4) O-Ring. Positioned on the threaded hub of the motor to provide a water proof seal between the filter and motor.

 

kc27, consider pivoting the pre-filter upward a bit instead of pointing straight down. This will give you more clearance between the substrate and the pre-filter.

Or the problem is that your samd wasn't rinsed thoroughly enough before putting it in the tank the first time.

Although it would be a PITA, consider removing the decor from tank then scope out all the sand and give it a good rinsing in a 5 gallon bucket and garden hose. Try to pour off from the bucket all the small grains of sand that stay suspended in the water while rinsing. When I rinse my sand, I know I'm done when all the grains of sand sink back down and not stay suspended in bucket of water after shooting a jet of water from the garden hose in it. That way when the sand is in my tanks, when the substrate is disturbed it all falls quickly back down and doesn't stay suspended in the water. This reduces the chance of getting sucked up into my filters.

ForceTen, when I can find the pics I took the last time I replaced a shaft on an AC70 I will post them, but the shaft was definitely had scoring on it.

Even though the impeller slips over the shaft, there is still a gap since the impeller rotates around the shaft. Although a small gap, the smaller grains of sand will still find their way in there over time.

Yes I agree that pre-filters on the end of intake tubes can be messy when cleaning, but I quickly found a way to solve that problem.

With the filter still running, I dunk a gallon sized ziploc bag in the water and then insert the prefilter and part of the intake tube into the bag.

I dont really zip the seal close, but just cinch the opening closed and either pull just the pre-filter off with its adapter connector, or pull it and the bottom intake tube off all together and lift it all put of the tank.

I can place it in a bucket or take it to a sink, and then I can go unplug the filter.

This will effectively trap almost all the muck released by the pre-filter when its removed and leaves no mess in the tank.

If a bit of muck does get released from the bag as it's removed, the filter will suck it up.

 

kc27, consider pivoting the pre-filter upward a bit instead of pointing straight down. This will give you more clearance between the substrate and the pre-filter.

Or the problem is that your samd wasn't rinsed thoroughly enough before putting it in the tank the first time.

Although it would be a PITA, consider removing the decor from tank then scope out all the sand and give it a good rinsing in a 5 gallon bucket and garden hose. Try to pour off from the bucket all the small grains of sand that stay suspended in the water while rinsing. When I rinse my sand, I know I'm done when all the grains of sand sink back down and not stay suspended in bucket of water after shooting a jet of water from the garden hose in it. That way when the sand is in my tanks, when the substrate is disturbed it all falls quickly back down and doesn't stay suspended in the water. This reduces the chance of getting sucked up into my filters.

ForceTen, when I can find the pics I took the last time I replaced a shaft on an AC70 I will post them, but the shaft was definitely had scoring on it.

Even though the impeller slips over the shaft, there is still a gap since the impeller rotates around the shaft. Although a small gap, the smaller grains of sand will still find their way in there over time.

Yes I agree that pre-filters on the end of intake tubes can be messy when cleaning, but I quickly found a way to solve that problem.

With the filter still running, I dunk a gallon sized ziploc bag in the water and then insert the prefilter and part of the intake tube into the bag.

I dont really zip the seal close, but just cinch the opening closed and either pull just the pre-filter off with its adapter connector, or pull it and the bottom intake tube off all together and lift it all put of the tank.

I can place it in a bucket or take it to a sink, and then I can go unplug the filter.

This will effectively trap almost all the muck released by the pre-filter when its removed and leaves no mess in the tank.

If a bit of muck does get released from the bag as it's removed, the filter will suck it up.

I see what you mean regarding the shaft and the sand. There is no doubt that sand in the intake and motor is an issue. And yes I can see particles getting in between the rotor and shaft.
I may need to pay special attention to this as my eyesight is not as good as it was 30 years ago.
I have used the plastic bag method for pre-filter removal and its about the only option you have. I have just decide not to use pre-filters and I am turning off filters until I am completely done before turning them back on again.
So far so good.
Make sure you push the shaft in all the way.