300 gallon preform filter?//

I have a 300 gallon preform and mech/bio beckett filters 2@ 350 gpm.
but raccoons took all my fish frogs and tutles after 3 years. This
really hurt. Anyway i put a green vinly coated metal (1/2 inch square
hole size) screen over it now. Both pumps are old one is dead. So I
needed a bio/mech. I bought a outside pond filter at a petshop that was
going out of buisness. I got a sunterra 2000 gallon with uv mech/bio
filter with a 1250 gph pump with prefilter. and bio ball for 100.00 he
said retail was 400.00. Anyone here of this brand? It looks good with a
course, medium and fine filter plus 40 bio balls. the filer says use
1250-2000 gallon pump. I want to run the filter plus put about 250 gph
into the bell fountain for oxygen. Is that ok? Im so used to the
becketts that I have to clean every 6-8 weeks. This one has a pressurred
claen option and uv. But he told me not to use the uv for 3 months cause
it will kill the good bacteria. Well it might be oversized but it sure
looks so easy to clean the course filter and leave the bio alone. What
you all think on this. I have 8 4 inch fish and 1 turtle that poops a
lot lol. Thanks