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Apples to Apples Hydroponics - Nutrients

NPK readings were for Nitrogen (N) only at first, due to lack of testing tablets, and pH. This reading was close to the October 11th setup time. When new tablets arrived the Phosphorous (P) and Potash (K) were measured, on December 2nd. Nitorgen readings had not changed, pH assumed the same in the fish and Micro solutions . P, and K showed a surprisingly high reading from the fish water, nutrients apparently not utilized as yet. The numeric measurements mean:

0 = Depleated
1 = Deficient
2 = Adequate
3 = Sufficient
4 = Surplus


Growth occurred as expected, in accordance with TDS, but there were some surprises. In general, germination was in step, due to the seedlings living off the seed nutrients. Thereafter a spread occurred.

  1. Fish water Nitrogen as well as other nutrients are produced steadily, so where they don't register, they are apparently there. Where the TDS was low, the Nitrogen (N) at rock bottom, the plants germinated and kept pace with the other environments, though more thin, with smaller leaves, fewer roots, and delayed growth in some cases. Watercress also continued Spinach sprouted in the fish water, but not in the other environments. Basil also appeared first in fish water, but soon died out. The rapid rush of water apparently encourages seedlings to spout. Pepper has yet to sprout, and the French Green Beans are struggling, barely putting out real leaves past the seed leaves.
  2. Worm water continued to increase in TDS over time, not diminish. This phemonenon is unexplained, but steady and not due to one daily aberation. The plants in the worm bed drainage solution also appear stronger, more green, with larger leaves, even though the overall TDS is lower than the Micro, and the flow tubes are further from the light. Basil also sprouted in the worm drainage water, though not in the Micro. The increase was from 983 on October 11th, to 1060 by December 2nd, to 1063 by December 5th, to 1118 by December 17th. The TDS in a 2 gallon reserve set aside at startup from the last drained from the bed (with a TDS of less than 983 at the time), showed an increase to 1510!
  3. Micro solution had to be replenished by December 5th, having fallen to a reading of 1224, which was expected. The Micro fell from 1297 on October 11th, to 1240 by December 2nd, to 1224 by December 5th. 1C of additional nurient solution was added on December 5th, bringing the TDS over 1300.