sand sifting star fish mating

[Ryanerickson]

Sand sifting stars are pseudocopulating, external fertilizers. They "mount" each other to get their gonads close together and increase the chances of fertilization, but they still release their gametes into the water to meet up

[iamfrontosa]

should i break them up? and toss one inside the sump? I don't want them to sour the tank.