Instead, they stimulate the growth of plants. The plants absorb the dissolved nitrates, generating hydroxide ions, which in return neutralize the excess acid. Removal of phosphates from detergent is not likely to slow algae growth in containing substances. It may actually prove disastrous. Its replacement with borax will definitely be disastrous.
Scientists are unsure of borax role in plant growth.
It is not required by algae and other micro plants, but it is essential to higher plants.