Just want to clarify your question, are you asking about root tabs for plants, for feeding plants in substrate?
If so, yes, these are good for plants, particularly for root feeding plants such as Cryptocorynes and vallisernias.
You can also use liquid fertiliser, usually once a week dosages, for other live plants such as floating plants, anubias and java ferns as these plants are not to be planted into the substrate. Instead they feed through their leaves and/or roots hence the liquid fertIlser to add nutrients into the water column.
I am not sure what is 5hem is, can you elaborate on this product?
I only have amazon sowrds and anubias. My Anubias are above the substrate although they have taken root also. My substrate is the tropica soil. If I got the root tabs for the amazon sowrds is it possible I could go without fertilising?
How long do you leave the tank lights on for during the day?
Does any sunlight go into the tank?
How much foods do you add into the tank per day?
How often and how much water changes do you do daily or per week?
I ask all these questions because there is no one single answer that could help you, there are usually several factors that makes algae appear in tanks.
Usually it’s down to lighting hours, 7-8 hours is the average times, any more light could increase the chances of problem algae.
Poor water quality could be factor in algae, too much foods into the tank could contribute to poor water quality.
Not enough water changes and tank maintenance can also add to the poor water quality. Most of us do at least 50% though would say it likely to be nearer to 70% of water changes once a week and cleaning tank glass of algae and syphoning up dead leaves, leftover foods and debris help keep water quality at a optimum level.
Direct sunlight into tanks can be a particular problem as this vastly increases the chance of algae appearing, particularly green algae.
So if you can reduce the sunlight going into the tank, this would help greatly, either by closing curtains/blinds or moving the tank to a more shaded area will be of great benefit.
The addition of ferts, be it root tabs or liquid ferts or both can contribute to algae, especially if you overdose the recommended amounts.
Algae, needs exactly the same as live plants in order to thrive, and if you have very few live plants then algae will take the lions share of these and thrive then problem algae will be in abundance, but if you have quite a few plants then the plants will take the lions share of the nutrients and such then the algae will simply starve and hopefully die off.
But if you follow all the above advice then algae should be well under control.
That’s fine, was not aware that you already knew this, it’s helpful for anyone else who may be reading this thread.
I find that liquid ferts are not essential but find more often than not that plants appreciate having this.
There is no fast and hard rules about adding ferts, there are some nicely planted tanks that grow well without any ferts at all whilst others are in dire need of ferts to help their plants thrive.
What works for one persons tank may well not work for another person tank as every tank is different. Even main water source differs, some water sources have nitrates, others have ammonia/ammonium and others have both which may explain why sone of these tanks do well without the addition of ferts as these are nutrients coming in from the water source itself.
You can try going without ferts and see how your tank goes, no way of knowing for certain until you try.