Selleys All Clear New Improved Formula and Aquariums

Is Selleys All Clear safe for use in aquariums?

No. All Clear is a solvent-based sealant and should not be used in aquariums. The only Selleys product recommended for safe use in an aquarium is Selleys Glass Silicone Sealant — and when using it, allow a full 7 days cure before filling the tank and adding fish.

The question behind the question was a good one: is All Clear excluded because it is toxic, or because it softens in water? The honest answer from the technical data sheet is that it is excluded on the immersion side, and that this holds regardless of whether there is any load on the sealant.

What the All Clear data sheet actually says

All Clear's limitations list four exclusions, and one of them names fish tanks directly:

• Not for permanent water immersion — e.g. fish tanks.
• May damage some plastics, e.g. polystyrene and polycarbonate.
• Not suitable for use over silicones.
• Not suitable for polystyrene foam.

Its service temperature is −10°C to +80°C, its technology is a co-polymer sealant, and its stated features include being water resistant — which is a different claim from being suitable for permanent immersion. All Clear is designed for water leakage and seepage around the home: window frames and glazing, roofs and gutters, stone, brick, cement and timber, shower screens, sinks and basins. All of those see water intermittently. None of them is a tank of water sitting against the sealant permanently.

Ornaments and load are not the issue. Even with no weight on the bond, the sealant is in permanent immersion, which is the condition the exclusion covers.

Glass Silicone — the product that is suitable

Property	Selleys Glass Silicone Sealant
Technology	Acetic cure, 100% silicone sealant
Colour	Clear
Packaging	75g tube; 310g cartridge
Skin time	5–10 minutes (weather dependent)
Curing rate	2mm per day
Cure	Sealant will cure in 72 hours
Aquarium cure before use	7 days
Elongation	Approx. 400% (ASTM D412)
Joint movement	±25%
Service temperature	Permanent −60°C to +150°C
Guarantee	25 years against cracking, crumbling or peeling away
Storage	Dry place below 30°C; use within 6 months of opening

Indicative data only, not intended for the preparation of specifications.

Glass Silicone is described as perfect for use on or around windows, window frames and aquariums, bonding to glass, glazed ceramics, porcelain, stainless steel, most woods, aluminium, many plastics, rubber and canvas.

The aquarium procedure, exactly as specified

The technical data sheet sets out the sequence, and each step is there for a reason:

1. Apply the sealant to clean, dry surfaces. Clean and dry the glass using mineral turpentine first.
2. Allow 7 days to cure. That is considerably longer than the 72-hour general cure figure, and the longer period is what the aquarium instruction specifies.
3. Thoroughly wash the tank out with water.
4. Drain it.
5. Refill before introducing fish.

The wash-and-drain step matters. It flushes out anything remaining on the surface of the cured sealant before the tank becomes a closed environment with livestock in it. Skipping it puts the first fish into water that has not been through that flush.

Two scope limits worth knowing

Small aquariums only. Glass Silicone is stated as suitable for constructing and repairing small aquariums. Large tanks require specialist design — the glass thickness, the joint design and the sealant all have to be engineered for the water pressure, and that is beyond a general purpose product. Selleys asks you to contact them if you are unsure.

Below-waterline use is otherwise excluded. Glass Silicone's limitations say it is not recommended for below-waterline applications, glass aquariums excepted. That exception is specific and does not extend to ponds, pools or tanks made from other materials.

Glass Silicone's other limitations

• Not recommended for use on concrete, cement products, zinc, or metals containing copper. Worth checking if there is any metalwork in or around the tank.
• Not for mirrors — Selleys directs you to Liquid Nails Mirror & Metal for those.
• Not paintable. Complete painting 7 days before applying the sealant.
• No AS/NZS 4020 certification for drinking water contact. Suitable for aquariums is not the same as suitable for drinking water — see is Glass Silicone safe for drinking water.

Safety: All Clear is excluded from the tank, and it is also the flammable one

The answer above turns on immersion. There is a second difference between these two products that is worth knowing before you use either of them in a fish room.

All Clear is classified hazardous with the signal word Danger: H225 (highly flammable liquid and vapour), H315 (causes skin irritation) and H319 (causes serious eye irritation). It is Dangerous Goods Class 3, UN 1133, Packing Group II — the same transport entry and packing group as a solvent-borne contact adhesive. Glass Silicone, the product this page recommends instead, is a rung down: signal word Warning, with H227 (combustible liquid), H319 and H317 (may cause an allergic skin reaction). So the product that is correct for the aquarium is also the less flammable one, which makes the choice easy.

Why H225 is worth taking seriously in this particular room. A fish room or a cabinet under a tank is a small, closed volume full of electrical equipment at low level — heater cords, air pumps, ballasts, filter motors and a power board, usually on the floor or on the shelf under the tank. H225 vapour is denser than air and settles, and a Category 2 flammable forms an ignitable mixture at ordinary room temperature. Work with the room open and the equipment switched off at the wall rather than assuming a sealed cabinet is safe because nothing has a flame in it.

If you are removing All Clear that is already in a tank, the page tells you to cut and scrape it, because there is no chemical remover published for cured All Clear. That is fortunate here: the removal step carries no solvent hazard. Do it with the tank drained and dry, with gloves and eye protection, and keep the shards out of the substrate.

For either product: nitrile gloves, safety glasses, no smoking, and wash your hands before handling food or fish food. A splash in the eye from either gets 15 minutes of irrigation with the eyelids held open, not a blink and a rinse.

Poisons Information Centre — 131 126 in Australia, 0800 764 766 in New Zealand.

Common questions about sealants and aquariums

Is All Clear excluded because it is toxic or because it softens?

The technical data sheet's stated limitation is that it is not for permanent water immersion, with fish tanks given as the example. That exclusion applies whether or not there is any load on the sealant.

Which Selleys product can I use in a fish tank?

Glass Silicone Sealant, with a full 7-day cure, then wash out, drain and refill before adding fish.

Why 7 days when the data sheet says it cures in 72 hours?

72 hours is the general cure figure. The aquarium instruction specifies 7 days, which is the longer, more conservative period for an application where the sealant will be permanently under water with livestock.

Can I use it to attach ornaments to the bottom of a tank?

Glass Silicone is suitable for constructing and repairing small aquariums, and bonds to glass, glazed ceramics, porcelain and many other materials. Follow the same 7-day cure and wash-out sequence before adding fish.

What about a large tank?

Specialist design is required for large tanks. Contact Selleys on 1300 555 205 if you are unsure whether yours qualifies.

Can I use a wet-area silicone instead?

No. No Mould, Wet Area Silicone and Wet Area Matt Silicone all state they are not suitable for aquariums.

What if I have already used All Clear in a tank?

Remove it. Cured All Clear is removed by cutting and scraping — its data sheet gives no chemical remover — and note that All Clear is also not suitable for use over silicones, so it should not be layered onto an existing silicone bead.

How do I prepare the glass?

Clean and dry the surface using mineral turpentine, then apply. Tool with a spatula dipped in soapy water and clean up before the sealant skins in 5–10 minutes.

What about a pond rather than an aquarium?

Different application — for plugging and rebuilding in a pond, Knead It Aqua is the product Selleys names. See plugging a hole in the bottom of pottery.