If you have a penguin filter your in luck instead of buying filter media made for the penguins buy media made fo the aqua-tech brand filters at wal-mart. they fit perfect because aqua-tech is actually a cheap brand from marineland. im not sure if there is any difference at all they both say series 133 on the back of the filter and they are exactly the same size. I think if there is any difference at all it is just a different type of carbon in it. I buy my filters for my penguin 350 and 200 from wal-mart for $10 for 6 filters. I would definetly rather pay that then the normal $16-20. just thought i would let all of you know a little secret.
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29g- saltwater
Penguin 350 filter
Sea-clone 100 skimmer
Maxijet 1200 powerhead
2x65W power compact with lunar lights
40-lbs live sand
35-lbs live rock
1-small female yellow tang
1-cardinal
2-false clowns
1-saphire damsel
55g-Cichlid
Emporer 400 filter
2 x Powersweep 228 powerhead for undergravel filter
1-8" red devil
1-7" black african knifefish
2-plecos (7"&13")
6-black convicts
20g-long
penguin 200 filter
black convict breeding pair with about 120 fry
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29g- saltwater
Penguin 350 filter
Sea-clone 100 skimmer
Maxijet 1200 powerhead
2x65W power compact with lunar lights
40-lbs live sand
35-lbs live rock
1-small female yellow tang
1-cardinal
2-false clowns
1-saphire damsel
55g-Cichlid
Emporer 400 filter
2 x Powersweep 228 powerhead for undergravel filter
1-8" red devil
1-7" black african knifefish
2-plecos (7"&13")
6-black convicts
20g-long
penguin 200 filter
black convict breeding pair with about 120 fry