Aquaponics FL

Inputs · Water

Source water in Florida: well, rain and city water

An aquaponic system loses 1 to 3 percent of its water a day and has to be topped up, so the water you add slowly sets the system's chemistry. In Florida that usually means one of three things: hard, alkaline well water from the limestone aquifer; city water treated with chlorine or chloramine; or soft rainwater. Each works with the right handling; pond and surface water should be avoided.1, 4, 5, 7, 8, 2

Why you need it1, 2, 3

FAO says new water sources should always be tested for pH, hardness, salinity, chlorine and pollutants. The main differences: rainwater is near neutral, very low in hardness and salt, and needs buffering; well water over limestone is hard and high in carbonate, which may keep pH above 7 and occasionally call for acid-treating the top-up water; city water carries chlorine or chloramine, which must be removed; reverse-osmosis water, like rain, needs buffering (FAO). SRAC 454 says municipal water should be used only once dechlorinated and surface water not at all, because of disease organisms; the UF/IFAS guide HS1252 likewise recommends well or city water for recirculating aquaponics, not pond water.

How to use it1, 2

Test before you commit. FAO's guide figures: hardness of about 60 to 140 mg/L (both general hardness and carbonate hardness, KH) suits aquaponics; source water is too salty above an electrical conductivity of about 1,500 microsiemens per cm or about 800 ppm total dissolved solids. SRAC 454 says sodium should stay under 50 mg/L, because more interferes with potassium and calcium uptake and causes tip burn. Rainwater: FAO calls collected rain an excellent source; buffer it (calcium carbonate, see pH adjusters), and treat roof water that may carry bird droppings before use. City water: dechlorinate or remove chloramine (see Dechlorinating tap water). Well water: if hard and alkaline, FAO suggests acid-treating a reservoir of top-up water rather than the system.

In Florida5, 4, 6, 2, 7, 8

UF/IFAS PI245 says most Florida groundwater comes from the Floridan aquifer, made of thick porous limestone, and that its dissolved-solid content varies greatly from place to place. UF/IFAS SL219 says much Florida well water is alkaline (pH 7.6 to 8.5) from contact with that calcium carbonate rock, and that a rise in a well's conductivity over time can mean the aquifer is turning brackish or that saltwater is intruding. UF/IFAS Marion County Extension says hardness ions are present throughout Florida groundwater, and that a water softener swaps hardness for sodium (removing 50 mg/L of hardness adds about 25 mg/L of sodium); against SRAC 454's 50 mg/L sodium limit, softened water is a poor choice for top-up. The UF/IFAS Extension Soil Testing Laboratory in Gainesville tests well water for calcium, magnesium, carbonates, iron, manganese, sodium, chloride, conductivity and pH (SL219). City supplies in Tampa and Pinellas County use chloramine (City of Tampa; Pinellas County).

Cautions1, 5, 4, 2, 3

Hardness scales differ between sources: FAO and UF/IFAS PI245 call water soft below 60 mg/L, moderately hard at 60 to 120, hard at 120 to 180 and very hard above 180; UF/IFAS SL219 uses 0 to 17 soft, 17 to 50 relatively soft, 50 to 120 moderately hard, 120 to 170 hard and above 170 very hard. Read your result against the scale your lab uses. Do not use pond or surface water (SRAC 454, HS1252). Do not top up a chloraminated system with untreated city water; FAO's rule is no more than 10 percent at a time, and only after testing for chlorine.

What to buy1, 4

What to ask for is a water test, not a product: FAO's list is pH, hardness, salinity, chlorine and pollutants; the UF/IFAS Extension Soil Testing Laboratory well test covers most of these (SL219). For your system, a freshwater kit that reads pH, GH and KH lets you watch the effect of top-ups (FAO).

What this page doesn't cover yet

  • No UF/IFAS source gives measured hardness or alkalinity for Florida wells by region. Softener sellers' pages with regional figures appeared in search and were not used; they contradict each other.
  • Hardness classification scales differ (FAO and PI245 versus SL219); both are shown.
  • The point that softened water is a poor top-up choice joins two sources (Marion County's sodium figure and SRAC 454's 50 mg/L limit); neither says it in those words.
  • No source covers Florida rainwater chemistry or roof-runoff rules specifically.
  • SL219's pH and conductivity notes are written for irrigation and household water, not aquaponics.

Sources

  1. Small-scale aquaponic food production: Integrated fish and plant farming (Somerville et al. 2014). Food and Agriculture Organization of the United Nations (FAO), FAO Fisheries and Aquaculture Technical Paper 589. Read 2026-11-02.
  2. Recirculating Aquaculture Tank Production Systems: Aquaponics—Integrating Fish and Plant Culture. Southern Regional Aquaculture Center (SRAC), SRAC 454. Read 2026-11-02.
  3. A Practical Guide for Aquaponics as an Alternative Enterprise (Tyson and Simonne 2014), archival copy. UF/IFAS Extension, EDIS, HS1252. Read 2026-11-02.
  4. Irrigation and Household Water Test and Interpretation (Mylavarapu). UF/IFAS Extension, EDIS, SL219. Read 2026-11-02.
  5. Water Quality and the Effectiveness of Pesticides (Fishel). UF/IFAS Extension, EDIS, PI245. Read 2026-11-02.
  6. Water Quality Series: Hard Water (Vicari 2021). UF/IFAS Extension Marion County. Read 2026-11-02.
  7. Chlorine Disinfection. City of Tampa Water Department. Read 2026-11-02.
  8. Facts About Chloramines. Pinellas County. Read 2026-11-02.

Restated in our own words from these documents, written 2026-11-02. Doses are the sources' figures; test your water before and after.

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