I've noticed that the new leaves of my Amazon Sword are coming in crippled
and curled. I've read that this is likely to a deficiency of calcium. I've
read that calcium rarely has to be added to the water as there is usually
enough in city tap water.

The plant load is fairly high with Java Fern, Hygro difformis and Crypts in
addition to the Sword. Possibly related is I added 3 onion plants about two
months ago. One lost its leaves right away and died, the others took longer
and are just bulbs right now. One of them had quite a bit of growth early on
but then stopped after a couple weeks. The fish load is at 23 in a 45gal
tank. Fish include cherry barbs, lemon and congo tetras, ottos, corys, a
clown loach and gouramis.

Note that I've been trying to overcome an recent algae problem. I've done
weekly water changes for the past 6 weeks (approx) to try and reduce my
phospates. Funny that the algae is gone, but phospate levels have not
reduced. I also began dosing PMDD daily about a week ago.

Aquarium water params:
pH: 7.2
GH: 4.5 deg
KH: 4.5 deg
NH3/NH4: undetected
NO2: undetected
NO3: undetected
PO4: 5+ppm

Any ideas to save the Sword (and onions) are much appreciated!

Thx,
Anton