tunze 9004 not skimming surface

[ajm83]

My Tunze 9004 is not skimming the surface scum off my tank.

It's second hand but the chap assures me it was working perfectly prior to sale (and I believe him).

It's been in my tank 15 days so I would think it's bedded in by now.

It's not producing a huge amount of skimmate either really. Some, but not a lot, and it's very light in colour. Water height is bang on the 'osmolator' line on the back. Air line is fully open.

Any ideas? I'm stumped


here's a pic, (ignore the bubbles,that's from me opening the skimmer to look inside - it's the patchy oil I mean)

 

[Str8linespeed]

Following along to see if I can improve mine as well.

 

[rvitko]

Raise the skimmer, the higher you raise it the more aggressive the surface skimming. When it is deeper it draws most of the water right below the surface, to get only the surface film, try placing it so only about 1/4 of the front intake is submerged.

 

[ajm83]

You are right, when you see it suck in food particles, you can see it takes 90% of the water from just under the surface.

I did try raising it but found that it wasn't producing any skimmate any more, as the bubbles weren't reaching the top and spilling over into the cup.

I suppose I need to find a sweet spot where it is both producing skimmate and taking in some surface scum.
Thanks for your help.

 

[Str8linespeed]

I hope you dont mind me jumping in as well, ajm83.

I have mine set about where you suggest Roger. Every 2-3 day I have to empty the cup as its full of brownish water. Its not the really thick skimmate like I see from other skimmers. does this style skimmer do more of a wet skim than a dry skim?

 

[rvitko]

I would double check that the air is not restricted, it should generally skim as long as the pump is getting water. Commonly the nipple on the pump for the air intake will clog with salt creep after a few months it may be a noticeable reduction.

 

[Str8linespeed]

I'll check that out. The valve to restrict the air should be all the way open as well correct?

 

[smatter]

Yes all the way open. I took mine off as I have never needed it.

 

[ajm83]

Okay so I raised it right up so only 1/4 of the grille is in the water, but it's still not sucking up the scum on the top. I just can't understand what's going on.

Video: https://www.youtube.com/watch?v=DxaOVQbRYS8&feature=youtu.be

See the bits floating around, those are tiny bits of flake food...They're not being sucked in at all!

It says in the manual that there should be a 'waterfall effect' but I can't imagine that's actually happening. As soon as I take the top clear section off, you can see the water level is not dropped at all. It's the same level as the rest of the tank.

I've opened it and checked the hose is not kinked etc. It all looks good as far as I can see. Impeller
spins cleanly etc.

 

[rvitko]

On the back of the skimmer there is a part that is indented, it has a roughly 1/2" hole that should be plugged, is it possible that plug is missing? Do you have any other symptoms like a lot of air bubbles escaping?

 

[ajm83]

On the back of the skimmer there is a part that is indented, it has a roughly 1/2" hole that should be plugged, is it possible that plug is missing? Do you have any other symptoms like a lot of air bubbles escaping?

Thanks so much for your help, i really do appreciate it

No symptoms I can see other than fairly weak skimming performance and plenty of surface scum. It's nearly silent and seems to be making froth. No salt creep or kinks in the hose inside.

One thing I just noticed is that this plastic shroud on the pump (that connects it to the big face plate) is open at the bottom, so it looks like it is going to suck in water from there rather than through the hole. Should there be a stopper in there?

Here's a pic of the white bung in the back - is that what you mean could be missing?

 

[rvitko]

Yes, that white/clear plug is present, the issue is you are missing this part so the water just recirculates inside. Usually missing that part results in a lot of exiting bubbles.

https://www.tunze.com/US/en/products/details.html?user_tunzeprod_pi1[prodid]=0900.110

 

[ajm83]

Yes, that white/clear plug is present, the issue is you are missing this part so the water just recirculates inside. Usually missing that part results in a lot of exiting bubbles.

https://www.tunze.com/US/en/products/details.html?user_tunzeprod_pi1[prodid]=0900.110

Absolutely amazing, thanks so much for that!



Sent from my A0001 using Tapatalk

 

[Str8linespeed]

That piece was laying in the box when I got mine. I searched all over and could not find out where it went. I know see where it goes, I'll pull my skimmer today and also install it.

 

[smatter]

It's going to work like a dream now!

 

[Str8linespeed]

Got to piece in, let's see how this sucker does over the next few days!

 

[ajm83]

I can't get one at short notice so I've made one, I actually see the water fall effect they were talking about in the manual now!

Hopefully the surface slick will be gone in the near future. [emoji41]

Sent from my A0001 using Tapatalk

 

[Str8linespeed]

I can't get one at short notice so I've made one, I actually see the water fall effect they were talking about in the manual now!

Hopefully the surface slick will be gone in the near future. [emoji41]

Sent from my A0001 using Tapatalk

Had to edit: yes even full blast mine has that effect now

 

[ajm83]

What water fall effect?

Raise the skimmer so the water is only just entering the grill. Remove the collection cup. Look downwards into the skimmer. The section at the front will be an inch or two below the normal water level.

Sent from my A0001 using Tapatalk

 

[Str8linespeed]

Lol, sorry I had to edit my other post. I was looking from the side and not down from the top. Yes, mine is doing that as well.

Thank you everyone for the help!