Tank & Rainwater
Tank Water Treatment. Chlorine-Free. ERMA Approved.
Forsana Tank Water Treatment keeps stored water safe without chlorine's taste, smell, or handling risk. Made in New Zealand.
Chlorine-free
No taste, no smell,
no bleach handling.
MPI-Approved
Registered for treating stored water in New Zealand.
House tank to farm stay
Domestic and commercial storage tanks.
Cheaper per litre
Than our competitors on shelf.
Get Tank Water Treatment
A small tank or trying it first, the size most households need, or the whole property in one order.
Try the Bottle
Tank Water Treatment · 1L
$26.99
- A small tank or bach
- Trying it before you commit to 3L
Tank Water Treatment 3L
Same 3 litres, one bottle instead of three
- Buy 3 x 1L bottles$80.97
- Buy 1 x 3L$64.99
Most households · $21.66 per litre
Unlocks free shipping
Complete Rural Hygiene Bundle
Power Cleaner + Everything Cleaner + Tank Water Treatment, 3L each
- Power Cleaner 6%, 3L refill$59.99
- Everything Cleaner 3%, 3L refill$49.99
- Tank Water Treatment, 3L refill$64.99
Over $110, free shipping (Ex. WA, NT, TAS)
Dose it right, for your tank
No mixing, no complicated ratios — follow the rate on the bottle for your tank size.
House tanks
- Dose to the rate on the bottle for your tank's litreage
- No taste, no smell, nothing to flush before drinking
Baches & rural properties
- Treat on refill or on a set schedule for static tanks
- Straightforward to dose and store between visits
Water clarity
- Treated water stays clear — no chlorine cloudiness
- Safe for washing, stock and drinking, dosed as directed
Tanker top-ups
- Dose as the tank fills so it mixes through the delivery
- Carted water is treated before it reaches the tap
What Tank & Rainwater Customers Are Saying
Real feedback from households and rural properties, on Tank Water Treatment and the same formula in our RV & Marine range.
Water tank care
The best
RV Water treatment liquid
Top rated service = top rated product
Caravan clean
Water tank care
The best
RV Water treatment liquid
Top rated service = top rated product
Caravan clean
Why not just chlorinate?
| Forsana Tank Water Treatment | Chlorine dosing | |
|---|---|---|
| Taste and smell | None | Noticeable, especially at higher doses |
| Handling | Straightforward to dose and store | Corrosive, needs careful storage |
| What it leaves behind | Breaks down toward water and oxygen | Chlorine by-products in the water |
1L or 3L? Which size do I need?
Both dose the same way, straight from the bottle. Pick by tank size and how often you treat.
Tank Water Treatment 1L
A small tank, a bach, or trying it before committing to the bigger size.
Shop 1L, $26.99
Tank Water Treatment 3L
$21.66 per litre — the size most households land on for ongoing dosing.
Shop 3L, $64.99Whole property, one order? The Complete Rural Hygiene Bundle adds Power Cleaner and Everything Cleaner 3L refills, for $148.72. Safe enough for your tank, safe enough for the whole family.
See the bundleBefore you start
- Dose to the rate on the bottle for your tank size.
- Not a substitute for boiling or filtration where local health guidance requires it for a specific contamination event.
How much do I use, and how often?
Pour into the top of the tank and spread across the surface. Disinfection is usually complete within 24 hours, but the water is safe to use sooner if needed. Use monthly for best results.
*For smaller tanks, use 10 ml per 100 litres of water.
Tank been unused for a while?
- Drain, clean and rinse thoroughly to remove any sediment or biofilm first.
- Then apply a shock dose before refilling and resuming normal use.
- For ongoing protection, treat every 28 days during regular use.
Questions people actually ask
Is it actually cheaper than what I'm already using?
Per litre of concentrate, usually yes. The 3L works out at $21.66 a litre, and one bottle covers a 30,000L tank on the regular dose. The full cost-per-tank comparison depends on your dosing rate and tank size.
What are the best treatments for water tanks?
Chlorine-free options like this one avoid the taste, smell and handling risk of chlorine while still treating for bacteria, viruses and algae.
How often should I treat my tank?
Follow the dosing schedule on the bottle for your tank size and usage — typically at each fill or on a set schedule for static tanks.
Can I drink tank water treated with this?
Yes — dosed as directed, it's formulated for water disinfection in domestic and commercial storage tanks, including drinking water systems. That's the use it's approved for.
Is it ERMA approved?
Yes — registered as HSR002684 on the ERMA/EPA Approved Water Treatment Chemicals list.
Where can I buy it — Mitre 10, Bunnings, my local store?
Use Find a Stockist for retail locations, or buy online here with free shipping over $110.
Safe tank water. No chlorine. Made in New Zealand.
Free shipping on orders over $110 across NZ and AU.