Is My Filtration Enough?

[sjcneedshelp321]

I will be getting 2 Dwarf Puffers and 3 Ottos in a 27.5 litre tank, i have a fluval 1+ so far, im thinking that this probably isn't enough as i know that dp are very messy, so what would you suggest? shall i just get another 1+ or...? Cheers

Sam