My number 1 tip against algae

Often our hard work get’s covered by unwanted guests in the form of algae. And it can be difficult at times to beat algae.

I’ve been struggling with algae too. And if I had to give you my best tip to minimize algae growth, it would be to use deionized water. Deionized water is pure water that is completely free of dissolved solids.

How does this help to beat algae?

Imagine this, you’re filling your tank after a water change with your tap water. But the tap water might have totally different water parameters than your tank water does.
I ran a couple of tests, and here are the results of the water in my tank
and the results of the water of my local tap water. Quite the difference, right!

We know algae thrive during imbalances, so why risk it? You put so much time and effort into building
your scape, and you don’t want it to get ruined by some algae.

As water is the most essential element in your tank, it has to be the best water you can get. We can spend a ton on lighting, CO2, fertilizer, etc. But water for your tank is like fuel for your car. Get it wrong, and it just won’t run.

What are the benefits of using deionized water?
  • Deionized water has a very low pH. Depending on your local tap water, you can achieve a pH of 5.5.
  • Deionized water has no dissolved solids, so you can match exactly your tank’s water parameters.
  • With deionized water, you won’t create significant imbalances after a water change in your tank.

This is beneficial for your plants and not so much for the algae.

When I discovered this, it all made sense

When I started my aquascaping journey, I had many problems with algae, and I tried everything to beat it, but it didn’t work out for me. Until I noticed something. Running a lot of tests, I figured that the balance of my tank was disturbed after a water change. And it took quite a while until the balance was restored, and these imbalances gave algae the chance to grow.

With deionized water, you can easily change the parameters of the water because it’s pure water. You can achieve any water parameters you like by adding tap water or a water remineralizer.

How do you get deionized water?

There are a couple of options, and the most common one is using an RO unit or a reverse osmosis unit in combination with a DI filter on top of it.

Reverse osmosis is a water purification process that uses a semi-permeable membrane to separate ions, unwanted molecules, and larger particles from tap water. This purification method requires an RO unit that you must permanently install next to your faucet. You also need to have a large tank to store all the water.
If you, like me, don’t have a lot of space to install a permanent RO unit and don’t want to generate a lot of water waste. A water purifier or DI filter could be a better option for you.
This is the unit I’m using. There are many other good options on the market, and they usually work pretty much the same.

How does it work

The system works with a hose connected to a faucet. The canister of the DI unit will be pressurized, and the water filling the canister has to pass through a resin bed. This resin bed will purify your tap water by exchanging hydrogen (H+) and hydroxyl (OH-) ions for dissolved minerals, then recombining to produce water (H2O). The dissolved minerals will eventually saturate the resin bed. The resin bed then has to be replaced. You can simply take the resin bed out of the DI unit and replace it with a new one. In this article, you can read more about the cost of running a DI filter.
The system doesn’t produce any water waste and can be stored anywhere after use.
The purified water has to be remineralized before you can use it for your tank. You can simply mix it with tap water until the preferred water parameters are reached, or you can use a reminalizer.

Final thoughts

I’ve been using this method since 2014, and it has helped me a lot.
Of course, it is another investment, but you’re already in the game. You want a good-looking tank, but algae are limiting your success. Water is the number 1 ingredient in your tank.
I’ve spent so much time and money trying to beat algae in my tanks. And I had temporary success with some methods/investments. But nothing ever helped me, like being a master of my water parameters.