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What’s the difference between Tetra SafeStart and SafeStart Plus?

If you are looking for a quick way to add live beneficial bacteria to your fish tank, then Tetra has two similar products with the SafeStart and SafeStart Plus. So, what are the main differences between these two bottles?

You can find out in this comparison article from Aquarium Blueprints.

Quick Summary

The SafeStart Plus contains double the concentration of live Nitrosomonas, Nitrosospira and Nitrospira bacteria strains when compared to the SafeStart.

So, if you want to cycle your fish tank or rebuild its biological filtration, then we recommend picking up the plus version.

If you don’t mind waiting for a little bit longer for your tank to cycle or for its biological filtration to build back up, then the normal SafeStart is the more affordable option out of these two products.

Tetra SafeStart vs. Tetra SafeStart Plus Comparison Chart

You can find our comparison table for the Tetra SafeStart and Tetra SafeStart Plus below.

Tetra SafeStartTetra SafeStart Plus
Size Options1.69 fl oz (or 50 ml)

3.38 fl oz (or 100 ml)

8.45 fl oz (or 250 ml)
1.69 fl oz (or 50 ml)

3.38 fl oz (or 100 ml)

8.45 fl oz (or 250 ml)
IngredientsPurified Water



Purified Water



Instructions for Cycling New TankUse full bottleUse full bottle
Instructions for Maintenance5 ml for every 10 gallons of 40 liters of tank water5 ml for every 10 gallons of 40 liters of tank water
Storage InstructionsDo not freeze.

Do not put close to heat source.
Do not freeze.

Do not put close to heat source.
Satisfaction Guarantee90 days90 days

Size Options

Both products are available in the following bottle sizes:

  • 1.69 fl oz (or 50 ml)
  • 3.38 fl oz (or 100 ml)
  • 8.45 fl oz (or 250 ml)


When it comes to ingredients, the liquid from these products composes of purified water to go along with live strains of various Nitrosomonas, Nitrosospira and Nitrospira bacteria species.

For the uninformed, Nitrosomonas will consume the ammonia from your tank water while Nitrosospira will help remove nitrites from your fish tank. The Nitrospira should help reduce nitrates in your aquarium.


The Tetra SafeStart contains a normal concertation of the aforementioned Nitrosomonas, Nitrosospira and Nitrospira strains.

The Tetra SafeStart+ should contain double the amount as SafeStart. Therefore, you should be able to get quicker results when cycling a new tank or trying to deal with spikes to the ammonia, nitrite and/or nitrate levels in your aquarium.

Instructions for Cycling New Tank

The instructions for using the SafeStart and SafeStart Plus are the same when it comes to cycling your new fish tank.

Tetra recommends that you use the entire bottle in order to kick start the biological filtration.

Instructions for Maintenance

The directions are also identical when it comes to the maintenance dose.

Tetra suggests that you add 5 mL of SafeStart or SafeStart Plus for every 10 gallons (or 4 liters) of tank water.

A maintenance dose can be used in the following scenarios:

  • After doing a water change.
  • After adding new fish to the tank.
  • After replacing a filter media.
  • Reduce the ammonia level.
  • Reduce the nitrite level.
  • Reduce the nitrate level.

Storage Instructions

These two products have the same storage instructions as well.

Tetra recommends that you store these bottles at room temperature as you should avoid putting them in a fridge. You should also avoid putting the products near a heat source.

Satisfaction Guarantee

Both of these products come with a 90 Days satisfaction guarantee.

If you aren’t satisfied with your bottle, then you send a written letter to Tetra in order to request a refund. You will need to include a receipt that shows that date of the purchase.

It may also take 6 to 8 weeks for your refund request to be processed.