Algae Control For My Sorority

[KrystaK]

So I have a 20 gal Sorority. I got them on Saturday from an auction, there are six girls and all are settled though 2 aren't doing well at all (they were in two different groups and it's 2 from the same group that aren't doing well but the third is doing very well)
 
Anyways this tank has always had algae problems, probably because it's by my living room window. But I don't know where I can move it to because my house is open concept so in the upstairs at least there is light everywhere.
 
Anyways my stock is:
6 Female bettas
3 Julie Corys
Assassin snails
 
What can I get as some Algae control while I debait on where to move the tank to so it won't be so in the sun? 
I can't get nitrate snails as my assassins will probably eat them..
K was thinking either some Otto's or a BNP, but I don't know which would be lighter on the bio load.
 
I know I need more corys, but if I had 6 corys I feel there wouldn't be any room for a school of Ottos, nor the BNP because I know they're rather messy for their size....
 
Any opinions?
 

 

[Wildbetta]

If you have enough other snails(MTS,ramshorn,ect) to feed your assasins or make sure they get some food from the bottom, they shouldn't really go after a nerite snail. I have nerites in almost all my tanks, one of which has 5 assasin snails.  I have never seen my assasins go after my nerite snails.  Not sure what to tell ya about the kind of algae you are having.  Otos only eat the really soft algae like diatoms(brown color that is often a symptom of the tank being new and not the harder surface algae.

 

[KrystaK]

Rats, i knew I should have bot a bag of snails at the auction
I'll have to go buy some plants and hope they have hitch hikers, snails are expensive around here!!!
 
 
I found that weighing down some Zucchini attracts the snails, would adding some to the tank to help feed the Assassins (And other snails if I find some) be acceptable? 

 

[Wildbetta]

The assasins eat meat based foods so shrimp pellets or other sinking food works for them.  Weighing down some kind of veggie is great for the other snails though.