My Angels are Breeding - Need Advise

Hi Everyone!

I am new to this forum, so I wanted to say a big howdy from a amateur fish keeper from Houston

Since I am limited on time here at work, I will get straight to my situation....

I have a 29g tank with a dual biofiltration system (changed out every 2.5 - 3 weeks) My tank temperature is set to 83 degrees and is stocked currently with:

2 Orange Crown Koi Angel Fish (they were small when i bought them but have since matured and are approx. 4 inches from tip to tip, vertically)

1 old male Betta

I have moved my giant Pecothimus (I know I spelled that wrong, he's an algea eater)
and my femal Betta outr of the tank because my Angels became highly agressive when they began the egg laying and fertilixing process.

SO.......my Angels began trying to breed about 2 months ago, but everytime I would see them laying and fertilizing their eggs (on the flat slate surface) an hour later the algea eater had eaten them all. So, last week when I saw the female laying again, I quickly set up an aux. tank and moved the algea eater and also turned off my filter so that they would not get sucked up and out....

Within three days the viable eggs had been moved repeatedly by the anxious Angels and were begining to show signs of life. However, my husband turned off the aquarium light and the following morning all of the little eggs with their squiggly protrutions were gone (I'm assuming that in the darkness they slif down into the gravel)

Are they dead and gone forever......should i put the algea eater back and turnt he filter back on.....or will they pop out of the gravel in a week or so?

This is my first experience with breeders.....The Angels seem distressed now. So, I don't know what to do for them.