Can there be such thing as too many copepods and amphipods?

So, a while back I seeded my tank with all kinds of copepods and amphipods from aquaculture nursery farms.

Combination of my tank being fishless, and me feeding phito, made their population boom.

I kid you not, anywhere I look in my sump or DT, I count at least 3..4 per square inch of the rock/surface. I must have 10,000 + in my tank. They are super active. Some are tiny (grain of salt size and I can only see them with mag glass), but most are getting huge, like small ant size. Few are as big as fire ants.

I am going to be fishless for another 8..9 weeks. Should I just let nature take it's course and keep feeding phito? Or am in danger of bad infestation?

Also, I noticed a lot of super tiny (grain of salt size) hydroid/jellyfish things all over my tank glass. They look like this:


Tank is sure alive, just not sure if it's a good or bad thing.

 

The Hydroid Jelly will die off, they always do.

Pod population is only going be regulated by available food source. You might see an issue with the larger Amphipods going after zonathids and LPS if you do not feed them. Until you see a real problem just feed them sparingly. You're going to have fish soon enough again.

 

that is a very cool critter Too bad they die off....

 

I try to kill my pods with Wrasse RX. The more wrasse you add after your fishless cycle the less headaches you'll have.