2. Precipitate removal
Over the long-term, it is sometimes useful to
conduct an acid flush to help remove precipitates (white precipitates of
calcium sulfate and phosphate – Fig 11.5) that cannot be dissolved with
plain water or wet brushing.
Step 1.
Firstly, treat system as detailed for “disease preventative” above.
Step
2.
To tank, add water and enough hydrochloric
acid** to achieve pH 2. i.e. if using rain or RO water, dilute 30%
hydrochloric acid (i.e. normal commercial strength) by around one thousand
fold i.e. 1ml per litre (3/4 tsp per Gal).
Step
3.
Soak system for 24 – 72 hours. While system
is soaking:
-
Re-circulating systems:
Run the pump for at least 15 minute cycles every hour.
-
Run-to-waste systems:
Run the pump for a short burst once every hour and collect the discharge.
Step
4.
Afterwards, neutralize solution up to pH 5 – 6 with soda ash before
discarding.
Step 5.
Flush whole system several times with fresh water to remove all traces of
acid, dislodged material, etc.
Step 6.
Where fine drippers, sprayers (etc) are used, it may be necessary to
individually dismantle and clean each unit.
** Ensure
to follow necessary safety precautions and contact no metal parts.
