Bread-Bakers v112.n010.6

I think the temperature and feeding schedule are the culprits.

If you're using equal weights of flour and water, then you're using 
what many people would call a "liquid" starter. (I use twice as much 
flour as water to produce a "firm" starter. Either is fine.

I wouldn't say that liquid starters become "foamy," but they do 
develop visible surface bubbles at the end of their growth phase, 
i.e., just before feeding.

However, your starter is not going to grow properly at refrigerator 
temperatures. The refrigerator is only for long-term storage.

What I do is go through a few refresh (i.e., feed)-and-grow cycles at 
room temperature and then store it in the fridge for a few weeks. 
Then I take it out of the refrigerator and repeat.

Finally, you're probably including way too much starter with each 
refreshment cycle. If you are doing two room temperature feedings a 
day (1 every 12 hours), then try using equal weights flour & water, 
and then 1/3 that weight of starter.

Allen
SHB
San Francisco