# HELP!!! Any Experienced Oase Biomaster Owners?



## EmotionalFescue (Jun 24, 2020)

Just peeked at amazon reviews and lots of folks seem to be having this issue. Must be sucking air in somehow. Not sure why it wouldn't do it consistently day and night though...


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## a modest aquarist (Jun 11, 2019)

I've owned various sizes of the Oase Biomaster Thermo and unfortunately it a problem that the 600 biomaster thermo is consistently having. I've heard of others who swapped the head unit out with success, but as you have already experienced by getting an entire new unit its really hit or miss. I've read on other forums that Oase has a new head design that fixes the issue, but I haven't seen anyone actually confirm it. 

The Eheim Pro series are similar in price and flow, but doesn't not include a heater like the Oase. They do have Pro series filters with built in heaters that cost a lot more though. Depending on your setup, I would probably go with the regular Eheim Pro series and hide a heater behind plants, wood, etc.

Also no personal experience using, but I've heard good things about the Fluval 7 series. The 407 is equivalent in GPH at 383, I think the 600 is 350 or so.


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## evil8 (Aug 7, 2018)

Run a bit of petroleum jelly around all the gaskets and o-rings and see if that helps your issue.


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## Cullen (Mar 2, 2013)

a modest aquarist said:


> I've owned various sizes of the Oase Biomaster Thermo and unfortunately it a problem that the 600 biomaster thermo is consistently having. I've heard of others who swapped the head unit out with success, but as you have already experienced by getting an entire new unit its really hit or miss. I've read on other forums that Oase has a new head design that fixes the issue, but I haven't seen anyone actually confirm it.
> 
> The Eheim Pro series are similar in price and flow, but doesn't not include a heater like the Oase. They do have Pro series filters with built in heaters that cost a lot more though. Depending on your setup, I would probably go with the regular Eheim Pro series and hide a heater behind plants, wood, etc.
> 
> Also no personal experience using, but I've heard good things about the Fluval 7 series. The 407 is equivalent in GPH at 383, I think the 600 is 350 or so.





a modest aquarist said:


> I've owned various sizes of the Oase Biomaster Thermo and unfortunately it a problem that the 600 biomaster thermo is consistently having. I've heard of others who swapped the head unit out with success, but as you have already experienced by getting an entire new unit its really hit or miss. I've read on other forums that Oase has a new head design that fixes the issue, but I haven't seen anyone actually confirm it.
> 
> The Eheim Pro series are similar in price and flow, but doesn't not include a heater like the Oase. They do have Pro series filters with built in heaters that cost a lot more though. Depending on your setup, I would probably go with the regular Eheim Pro series and hide a heater behind plants, wood, etc.
> 
> Also no personal experience using, but I've heard good things about the Fluval 7 series. The 407 is equivalent in GPH at 383, I think the 600 is 350 or so.


Thanks for the input. Both the original and replacement head unit have the new design, so I guess it’s just not going to happen with this brand. Too bad.

I already bought an eheim pro 4 600 as a potential replacement (I saw it on sale and figure I could return if I got the oase working). I’m really unimpressed with the build quality. I’ve never tried a fluval filter, but maybe I should give it a try. What is going on with canister filters these days?!


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## EmotionalFescue (Jun 24, 2020)

for what it's worth, i've owned the fluval 107, 206, 307, and fx4 and they're all very good. the xx7 series especially is way quiet.


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## dornblaser (Sep 8, 2020)

Another recommendation for the Fluval 407.


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## Cullen (Mar 2, 2013)

dornblaser said:


> Another recommendation for the Fluval 407.


The flow rate of the 407 is pretty low (245) and I’m looking to upgrade from the eheim 2217 (263). The jump to the fx4 is mind boggling (450). Something in the 325-350 range is ideal but I don’t think fluval makes such a filter.


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## jellopuddinpop (Dec 12, 2016)

I've seen someone mention a.) making sure the hoses are cut at right angles, and b.) adding hose clamps to the connections. Both of those are super simple to try, so I would give it a shot. Worst case, you're out $2 for hose clamps.


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## EmotionalFescue (Jun 24, 2020)

Looks like 407 is rated at 383gph



https://fluvalaquatics.com/us/07-series-canister-filter/


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## Cullen (Mar 2, 2013)

EmotionalFescue said:


> Looks like 407 is rated at 383gph
> 
> 
> 
> https://fluvalaquatics.com/us/07-series-canister-filter/


That’s the pump rating, not the flow rate of the canister filter. For example the fx4 pump is capable of over 700, but the rating of the entire filter is 450 (without media).


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## EmotionalFescue (Jun 24, 2020)

Cullen said:


> That’s the pump rating, not the flow rate of the canister filter. For example the fx4 pump is capable of over 700, but the rating of the entire filter is 450 (without media).


Gotcha. Does fluval report out that spec or are you getting it from a rating site or something like that?


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## Cullen (Mar 2, 2013)

EmotionalFescue said:


> Gotcha. Does fluval report out that spec or are you getting it from a rating site or something like that?


In this case I just researched, but I know eheim and oase post their flow rates (without media) right on the box. Fluval seems to boast about their pump rate from what I can tell, which means nothing.


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## ZChalk (Jan 13, 2021)

Are you having water quality issues? If it's a planted aquarium you probably don't need more biological filtration. I could understand if it is a FO tank or maybe an overstocked tank with a lots of messy fish like goldfish or cichlids. 

In reality, you probably just need the canister for mechanical or chemical filtration. If you are concerned about flow in the tank a power head might be more useful in that you can target specific areas. 

A lot of people like to over compensate thinking they will be better off. I do it all the time, it gives us that sense of added comfort or fulfills a want... But you got to ask yourself if it is truly necessary.


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## Cullen (Mar 2, 2013)

ZChalk said:


> Are you having water quality issues? If it's a planted aquarium you probably don't need more biological filtration. I could understand if it is a FO tank or maybe an overstocked tank with a lots of messy fish like goldfish or cichlids.
> 
> In reality, you probably just need the canister for mechanical or chemical filtration. If you are concerned about flow in the tank a power head might be more useful in that you can target specific areas.
> 
> A lot of people like to over compensate thinking they will be better off. I do it all the time, it gives us that sense of added comfort or fulfills a want... But you got to ask yourself if it is truly necessary.


No water quality issues, but there are several reasons I need a bigger filter:

Wanted to get the heater out of the tank, and an inline wasn’t an option since I only have one filter and it’s already powering a reactor.
I’ve read from several sources, including 2hr and Tom Barr, that a planted tank should be turned over at least five times per hour. My eheim is probably only doing three. Now I do have a gentle power head that helps with circulation, but I’m aware the tank is under filtered.
I also plan to semi heavily stock this tank, which puts more strain on the filter.
However, the immediate reason I bought the oase filter was to optimize my CO2 reactor. I have the GLA reactor which needs an abundance of pressure/flow to work correctly. When underpowered the chamber fills with CO2 faster than the water can absorb, and it starts sloshing around.


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## mourip (Mar 15, 2020)

I have owned two Biomaster Thermo filters, a 250 and currently the 600. My 600 has plenty of flow for my 75 gallon with scape adjusted for good circular flow. It does not pull in air. After opening it up I do need to burp it but then it works great. Have you called Oase? They do have tech support and are very responsive.

The other idea is that your seals may not be in place properly. You may need to check them and possibly use a bit of petroleum jelly to help with the seal. I had to do that when I first got mine. Also if you have a lily pipe surface skimmer it may need adjusting to avoid pulling in air.

Let us know how it goes. I love my Biomaster. Having the removable prefilter will make any initial setup well worth it.


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## Cullen (Mar 2, 2013)

mourip said:


> I have owned two Biomaster Thermo filters, a 250 and currently the 600. My 600 has plenty of flow for my 75 gallon with scape adjusted for good circular flow. It does not pull in air. After opening it up I do need to burp it but then it works great. Have you called Oase? They do have tech support and are very responsive.
> 
> The other idea is that your seals may not be in place properly. You may need to check them and possibly use a bit of petroleum jelly to help with the seal. I had to do that when I first got mine. Also if you have a lily pipe surface skimmer it may need adjusting to avoid pulling in air.
> 
> Let us know how it goes. I love my Biomaster. Having the removable prefilter will make any initial setup well worth it.


No surface skimmer lily pipe and I have spoken with oase customer service extensively. They are super nice but also not super helpful. They have admitted this is a very common problem.

i will try the petroleum jelly on the seals to see if that helps. Seems almost too simple but I’ll try anything at this point.



Nicecook said:


> I do own 2 OASE Biomaster Thermo 600 with no issues, they've been running for 4-5 months. At the beginning they were pulling air but after tilting them to the sides it stopped. I do have a reactor connected to one of them and no issues, before I had a diffuser and no issues either. I did the same as you, increased holes in the prefilter tubes. I remember I took one of the blue big sponges out. Amazing filters!!


You leave them permanently tilted? Or you just did that to initially purge air?


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## Cullen (Mar 2, 2013)

Cullen said:


> No surface skimmer lily pipe and I have spoken with oase customer service extensively. They are super nice but also not super helpful. They have admitted this is a very common problem.
> 
> i will try the petroleum jelly on the seals to see if that helps. Seems almost too simple but I’ll try anything at this point.


Tried petroleum jelly this morning. Filter is the same.


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## P.Isley (Feb 18, 2020)

Cullen said:


> Tried petroleum jelly this morning. Filter is the same.


Bummer about the petroleum jelly. Fixes everything for me. It is a bit counterintuitive as you need to use a butter knife or something similar to pry out the o- ring flange. But pull it out, clean it off, lube it up and mine work great. I have three - a 600, a 350 and 250. Best canister filters I’ve owned, hands down.


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## szwamp (Feb 23, 2019)

The mistake here was going from the most reliable and trouble free canister filter of all time to an Oase. I have a 2217 that has been in continuous use for 22 years now without a single issue. Think about that, 24 hours a day, 365 days a year, 22 years and its running the very moment im writing this. Literally the only time its stopped in that entire 22 years is for monthly maintenance and the every other year swap out of the O ring, thats it.

I cant speak for any of the newer Eheim models but the Classic line is the most reliable and trouble free canister filter available. 

Id just go back to using the 2217 and forget about ever changing it again. Add a power head for increased flow, done.


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## AquaCarl (Mar 16, 2021)

I have had the Biomaster Thermo 250 for about 2 months and haven't had any issues. Using matrix and purigen along with aftermarket inflow (w/skimmer)/outflow pipes but otherwise no special treatment. It coughs up some air when you first start it up but that's it.


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## Raith (Jun 27, 2014)

I am in the same boat as you, OP; well, sort of. I was going to upgrade my filter, from EHEIM 2215 to the Filtosmart 200, but even reading those models, some folks have stated there were 'random noise' at exact intervals (perhaps coincidence).


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## cherry10 (Apr 9, 2021)

For what it's worth, make sure your intake side (inlet strainer, inlet pipe, inlet tubing) isn't too restricted. Both my Fluval 307 and Filstar XP3 began purging air at regular intervals when I neglected to clean the sponge re-filter I had on the intake tubing. It seems the restriction caused the pump to create sufficient negative pressure for the filter to pull in air from any other tiny gaps available. The system never leaked water.

So check to see if your intake tubing has any kind of restriction. Make sure there isn't excess debris or mulm that's restricting the intake tubing or strainer. What kind of intake tubing are you using?


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## evil8 (Aug 7, 2018)

Cullen said:


> Tried petroleum jelly this morning. Filter is the same.


I pulled my Filtosmart Thermo 100 apart on Friday night as it was sucking air again. I rinsed the sponges, cleaned the impeller and wiped the edges where the top and canister meet on both parts. Put it back together and it will work fine for a month or two and then start sucking air again. I now have 4 different sizes of Oase canister filter on 4 different tanks and this one is the only one that has chronic issues with air. Jelly works, but I don't really think the issue is the gaskets (obviously the petroleum jelly is to keep the gaskets from drying out). I don't think this particular canister's top locking mechanism holds it all tight enough. It's not an issue on the 200 that has the same design.


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## volcom6981 (May 16, 2021)

So I know this thread is older, but setting up a new planted tank looking to put together my equipment list, and saw this thread. I had myself set on this filter till I read all of this, and even on amazon. It’s amazing how many on YouTube give good reviews, and maybe it’s the luck of the draw, but it’s a lot of money to hope your the lucky one. So it seems like this is still a problem to this day? I take it most of you moved on from this filter then?


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## mourip (Mar 15, 2020)

volcom6981 said:


> I take it most of you moved on from this filter then?


I still have a 600 on my 75g tank and a 250 as an emergency backup. It is working really well. When I first received it I had to remove the large "O" ring and use a bit of petroleum jelly on it but have had no issues in 6 months of use. My understanding is that a modification for the part that holds the impeller in place solved this issue for most users. For anyone still having the issue you also might try removing the impeller and reseating it. It will need cleaning periodically regardless as it tends to get coated with detritus.

One other place to check is the seal for the heater.


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## Cullen (Mar 2, 2013)

In the end I kept the filter, despite the issues. The air purging has calmed down some, unless I move the filter whatsoever, then a huge blast of air starts flowing out. I also put it on my reactor so the bubbles just get caught in there, and not all over the tank.

I have run into several more people locally who have the same issue, all with CO2 injected tanks. It seems it’s a very common problem for the planted tank community. But we just all have decided the benefits outweigh the problems.


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## mourip (Mar 15, 2020)

Cullen said:


> In the end I kept the filter, despite the issues. The air purging has calmed down some, unless I move the filter whatsoever, then a huge blast of air starts flowing out. I also put it on my reactor so the bubbles just get caught in there, and not all over the tank.
> 
> I have run into several more people locally who have the same issue, all with CO2 injected tanks. It seems it’s a very common problem for the planted tank community. But we just all have decided the benefits outweigh the problems.


Glad to hear that you stuck with it. The built-in heater and prefilter make the Oase really great to work with.

Unless you have an inline diffusor connected to your filter input instead of your output, or an in-tank diffusor placed next to your in-tank filter input, I do not see how CO2 could cause gas buildup.

One other thing. When I do my weekly water change and remove my prefilter to clean it I always burp the cannister once it starts back up. I rock it, and hold for a couple of seconds, in all 4 directions a couple of times and then it is good until the next water/prefilter change.

A tip: buy a second set of prefilter sponges to rotate. They are cheap and it makes the prefilter service take just a couple of minutes. You get the refreshed prefilter back in quickly and then you can take your time cleaning the dirty set. I use 45ppi to cut down on needing to clean the main cannister as often.


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## volcom6981 (May 16, 2021)

On a 40 gallon breeder size tank is the 350 enough, or do I need the 600?


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## Cullen (Mar 2, 2013)

volcom6981 said:


> On a 40 gallon breeder size tank is the 350 enough, or do I need the 600?


350 would be enough. 600 would be overkill.



mourip said:


> Glad to hear that you stuck with it. The built-in heater and prefilter make the Oase really great to work with.
> 
> Unless you have an inline diffusor connected to your filter input instead of your output, or an in-tank diffusor placed next to your in-tank filter input, I do not see how CO2 could cause gas buildup.
> 
> ...


I have an extra set of sponges. And believe me, I was burping the crap out of that thing. And if you read this entire thread, you’ll see the great lengths I went through to try to overcome the purging problem.

The company seems to know there is a still a problem with their filters, which especially affects those with CO2. It can’t be a coincidence that I’ve spoken to over a dozen biomaster 600 owners who have planted tanks, and they ALL have air purging issues to one degree or another. I can’t explain why it is happening, but all evidence points to CO2 injected tanks.

I just want anyone who is jumping into Oase to understand, while it has lots of pluses, the air purging is a widespread issue and is very annoying.


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## AquaCarl (Mar 16, 2021)

My 250 is still going strong since I last posted. I had a slight rattling sound develop about 4 months into operation that went away after cleaning the impeller (there was a decent amount of bio-goop buildup on it). Maybe the issue is with 600 models only and/or a particular batch of models.


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## mourip (Mar 15, 2020)

AquaCarl said:


> My 250 is still going strong since I last posted. I had a slight rattling sound develop about 4 months into operation that went away after cleaning the impeller (there was a decent amount of bio-goop buildup on it). Maybe the issue is with 600 models only and/or a particular batch of models.


I have a 250 and a 600. They will slow down and eventually develop a click if you do not clean the impeller periodically. This is probably true for all canister filters.

OP should contact Oase to get a new head unit under warranty replacement. Their support is excellent.

Better to turn on a light than to curse the darkness?


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## Nicecook (Mar 31, 2021)

I had to cleaned one of my 2 OASE 600 yesterday, I noticed some leaves floating in the tank and for me that is a sign of something going on, it had little flow. So, in order to keep them running in optimal conditions I have to clean the pre-filter sponges every 2 months. How often you change those? I mean new ones.


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## mourip (Mar 15, 2020)

Nicecook said:


> I had to cleaned one of my 2 OASE 600 yesterday, I noticed some leaves floating in the tank and for me that is a sign of something going on, it had little flow. So, in order to keep them running in optimal conditions I have to clean the pre-filter sponges every 2 months. How often you change those? I mean new ones.


I clean my prefilter when I do my weekly water change. If you get a second set of sponges it just takes a couple of minutes. It will help with flow. 

I also drilled more holes to the prefilter intake tube and opened up the existing ones a bit.

I only open up the main filter every 6 to 8 weeks or when I hear the pump start to hum. That hum usually means that the impeller is collecting detritus.


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## volcom6981 (May 16, 2021)

Which pre filter are you guys using. It comes with the black which I think is the 60. I switched to the orange which is the 30, but wondering if the 45 would be better?


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## mourip (Mar 15, 2020)

volcom6981 said:


> Which pre filter are you guys using. It comes with the black which I think is the 60. I switched to the orange which is the 30, but wondering if the 45 would be better?


I switched from the stock black 60 prefilter sponges to the blue 45. I was afraid that the orange 30 would allow too much detritus to clog the main sponges and biofilter media.


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## AquaCarl (Mar 16, 2021)

Maybe someone else can confirm or deny but I think I remember reading the black ones are carbon sponges.


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## Nicecook (Mar 31, 2021)

AquaCarl said:


> Maybe someone else can confirm or deny but I think I remember reading the black ones are carbon sponges.


It is confusing, when I bought mine I was checking all the sponges and I could not figure out if the black ones are carbon or not?



mourip said:


> I switched from the stock black 60 prefilter sponges to the blue 45. I was afraid that the orange 30 would allow too much detritus to clog the main sponges and biofilter media.


How are the blue ones? I still have the black ones that come with after 10 months and they seem fine. Do you know when to change them?

Also I did as you sugguested, I clean the prefilter sponges every month and it seems to help. Thanks!!


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## volcom6981 (May 16, 2021)

I saw a video that said the black ones are carbon, but nowhere on the package does it say this, only says it’s the 60. I have all 3 now I’m using the orange 30 right now and will switch to the blue 45 next just to see. It also looked like they used to only send the blue ones, wonder why they switched to sending the black 60 with it.


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## mourip (Mar 15, 2020)

volcom6981 said:


> I saw a video that said the black ones are carbon, but nowhere on the package does it say this, only says it’s the 60. I have all 3 now I’m using the orange 30 right now and will switch to the blue 45 next just to see. It also looked like they used to only send the blue ones, wonder why they switched to sending the black 60 with it.


The carbon are black but so are the included ones that are not carbon. Poor planning on the part of Oase!

I use the blue ones. I pull the prefilter and swap out the blue ones for a second set to make things easier. I do this every week with my water change. I tried the orange ones briefly thinking that they might increase the flow but that did not seem to be the case so I went back to blue in order to keep the main filter media from getting clogged too fast.

I also put the Bloody Mary neo shrimp back into the tank as they like to ride the intake slide into the prefilter.

I clean the main filter trays every couple of months ...or so


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## mourip (Mar 15, 2020)

Nicecook said:


> Do you know when to change them?


They seem to last forever you just need to rinse them out thoroughly.


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## Spike the BNP (Sep 2, 2013)

So, what's the verdict? I see that the OP has kept his Biomaster. I have an Eheim 2215, which I like because it has very few points of failure. Products like the Oase Biomaster scare me because of how many different points of failure they introduce with the heater and prefilter sections that are removable and have their own seals. Have those of you who own Biomasters been satisfied? I'm like the guy with the 2217 earlier in this thread, but my 2215 has only been running for 8 years. All I've replaced is the impeller, which was problematic from the start (Chinese, not German?), and the replacement (which was definitely made in Germany) gave me the silence the Classics are known for. Was it worth it to change to something more complicated?


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## prodicus (Dec 4, 2021)

Cullen said:


> I recently upgraded the canister on my 50g from an Eheim classic 2217 to an Oase Biomaster 600 Thermo. I was looking for a filter that has more flow, more space for biomedia, and an integrated heater. On paper this filter looks perfect, and so many sources have recommended it for use in planted tanks (2hr aquarist, GreenLeaf Aquariums, several LFS, etc.). In person the filter is great too... solid build quality, snazzy prefilter chamber, solid heater, good flow (after some mods). But I've run into the most frustrating issue pertaining to air buildup and, after doing a ton of research, it seems this is a somewhat common problem for Biomaster users, and especially those using the 600.
> 
> Around 2pm every day the filter starts to purge little bits of air every 10-15 minutes. If you rock the filter whatsoever there is so much air escaping that the impeller almost stalls. It continues like this until well into the evening until, presumably, the air has dissolved enough to cease the air purging. I assume the filter is sucking air from off-gassing plants, but its seriously a TON OF AIR! And why was my eheim not afflicted with the same issue? The intake is in the exact same place.
> 
> ...


I had the same problem. What solved the issue for me: Make sure your spray bar and intake valves are wide open. Ie., don't restrict the outflow or inflow.



cherry10 said:


> For what it's worth, make sure your intake side (inlet strainer, inlet pipe, inlet tubing) isn't too restricted. Both my Fluval 307 and Filstar XP3 began purging air at regular intervals when I neglected to clean the sponge re-filter I had on the intake tubing. It seems the restriction caused the pump to create sufficient negative pressure for the filter to pull in air from any other tiny gaps available. The system never leaked water.
> 
> So check to see if your intake tubing has any kind of restriction. Make sure there isn't excess debris or mulm that's restricting the intake tubing or strainer. What kind of intake tubing are you using?


My intake and spray bar have valves. I had the air purging issue until I made sure they were both wide open -- especially the spray bar.


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## cah123 (12 mo ago)

The problem for me is in the valves in the right angle pieces are leaking. You can check this by putting a bright led light on your intake tube of your filter. If you see any bubbles going in over time they will accumulate and cavitate.


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