We've done the hard work looking for products which make fertilising your
Easy Aquascape simple. There is a lot of confusion out there on this topic so
admittedly there is a little bit of sciencey stuff here, but only to explain
why it can be so easy to keep your plants happy! Happy plants means healthier
growth which should outcompete any algae.
The beginner researching the topic of plant fertilisation will find the internet awash (excuse the pun!) with a multitude of articles about different nutrients that plants require in different quantities to grow healthily. These are not incorrect, they simply assume that there are no other limiting factors to plant growth in the aquarium. When this is the case any deficiency in one nutrient causes an imbalance which is what algae specialise in taking advantage of. However, as many new to the hobby do not dose pressurised CO2 (liquid carbon doesn't count here, as it is perhaps by as much as ten times less effective) due to expense, complexity, and perceived risks, this element required for plant growth will always be limiting. This then means that the internet is also full of stories whereby following dosing fertilisers for the first time, and perhaps only one specific nutrient to 'trial it', aquarists experience algae outbreaks which puts off many from trying fertilisers. This raises an important point; algae does not necessarily grow when nutrients are in mild excess, providing there is not too much of one kind of nutrient.
Now to the science... plants require 2 main types of nutrients; macro nutrients such as nitrogen, phosphorus and potassium, which they require in larger quantities, and micro nutrients which are a much broader group and are required in smaller quantities. Often the macro nutrients are sold separately and the micro nutrients as a combined product. Small regular dosing of micro nutrients will show benefits in some aquariums, however, this is only when either fish or plant stocking is high, or both. This is because fish food and the fish themselves will provide small quantities of the macro elements to a tank through waste products. Often however, without a daily water change regime, the micro nutrients present in tap water (just like natural mineral/spring water) get depleted by the plants. What is really required though is both types of nutrients to be available in slight excess so that plants are never left 'hungry'.
What you are looking for then in a fertiliser, or combination of fertilisers, is a mixture of macro and micro nutrients. This is a rare thing as stabilisers are required to prevent one type reacting with the other in the bottle. One combined product we would highly recommend is The Aquascaper Complete Liquid Plant Food (produced with input from George Farmer, YouTuber and planted aquarium specialist). This product is a one bottle marvel and Matt uses it on all his aquascapes because it makes dosing hassle free. Alternatively, you will need to purchase individually a micro fertiliser and compete macro fertiliser. There are many available in convenient soap dispenser type bottles. You'll ideally want liquid fertilisers, just to avoid added faff and so that someone else can take care of getting the quantities right for you.
Something we've not covered yet is how different plants take up their nutrients. You'll find more about this in the Easy Plants article but suffice to say some take most of their nutrients from the water column, others prefer to take it up via their roots. For plants such as these, it is important to provide nutrients in the substrate. This can be done in multiple different ways, but one foolproof method to supplement the nutrients available to an individual plants roots is via the use of root tabs. These are pushed into the substrate at the base of any plant which will benefit from it. There are a lot of different products out there, and most are very good, even some of the cheaper ones, so no need to be too fussy here. Just add another in the same location at the frequency recommended in the instructions as they have a finite life. This will really boost root feeder growth rates and plant health.
Most manufacturers recommend weekly dosing of liquid fertilisers. Please feel entirely free to ignore them! Consider if you fed your fish like this, they would go through periods of feast and famine and ultimately would not be healthy as a result, they would therefore be open to predation were they to be in the wild. The same applies to your plants though rather than predation, rather there is the threat of algae as we outlined above. Plants need nutrients on constant slight excess to ensure they always have what they need, whether it be a specific micro element or one of the macro elements, depending on the exact demands of the mixture of species in your tank. This will also provide excess available to be absorbed into the substrate (see this article for more detail). So give your plants a stable daily dose slightly in excess of the recommended amounts. You should do large weekly water changes to accompany this dosing regime, to prevent anything going too far into excess which provides an opportunity for algae to take hold.
Make dosing ferts part of your morning routine or do it when you feed the fish.
Buy yourself a 'python' or garden hose tap connector to make water changes quicker and easier... you won't regret it in the long term.
Tweaking your dosing!
To ensure that you are dosing the right amount of fertiliser, you can use 2 measures, the first is nitrate levels in your aquarium. Use your aquarium test kit to test post-weekly water change nitrate levels and compare this to pre water change nitrate levels. Try and keep the total increase in nitrate over the week to less than 20 to 30ppm.
The other measure to use is Iron - you can normally buy a test kit for this separately. It should indicate the correct amount of iron to be present in a planted tank on the colour chart. You can use this to experiment with your daily dosing amount until you get a stable reading in the right range after a couple of weeks.
If you have a heavily stocked tank, use complete products with care as they could lead you to experiencing high nitrate levels in your aquarium which is dangerous to fish health. In heavily stocked aquaria we recommend that you have a separate macro and micro fertiliser so that you can tweak the levels as appropriate.
Let us know how you get along using the techniques we have described above
in the comments section below. Also feel free to ask for any advice or support and
we'll try and come back to you ASAP.