Dealing with algae in new tanks

Today, we look at a common yet often misunderstood approach to algae on plants in newly planted tanks, such as the case in the picture above, where a hazy carpet of hair algae covers the newly planted Utricularia graminifolia. Another example below:

You are not wrong

Basically, if algae prefers to attach to plants (rather than hardscape), it is a sign that the plants are struggling.
Strong, healthy plants are very resistant to algae.

In a new tank (less than 3 months old), it is common for plants to get an initial bout of algae.
Often these are of the filamentous variety (hair / thread / deer horn etc).
Such algae can appear suddenly, even if the plants were initially free of algae, within the first 1 or 2 weeks after planting.

This can be caused by many things, but is basically due to the fact that the plants are still adapting to the tank environment.
Plants adapt by redirecting their energy to new leaves, so the newest leaves often remain free of algae while the older leaves are attacked by algae, as seen in the picture of the Monte Carlo below:

What not to do

In other words, the instinct to 'adjust something' is understandable but often counter-productive. 

What should I do?

• If you have already shaken the tank a little too much, the quickest way to recover is probably (unfortunately) a reset. Remove the algae infested plants and put in a new community. This is because while plants generally recover, severely algae-infested plants that have been in an unstable environment can take many weeks or even months to recover. This is too long for most hobbyists.
  
  When putting in new plants, it is important to attain ‘critical planted mass’. A rule of thumb is to cover at least 70% of the substrate with plants. 
  
  
• Review plant selection. Do your plants even fit the tank environment? Do they have enough light and CO2 for the species selected?
  
  Many plants look similar, but have vastly different needs, as we compare, for instance, HC Cuba and Monte Carlo.
  Are you trying to grow soft water plants in hard water (or vice versa?)
  
  
• If the plants fit the environment, the best but hardest thing to do (as we are all impatient) is to just keep things stable (don't fiddle with changes in light, food, flow) and let nature work its magic.
  For a tank with CO2 injection, it often takes 2-3 weeks for new plants to acclimate. For tanks without CO2 injection, it takes much longer - 45 to 70 days is common and natural (as the growth rate is 5X-10X slower without injected CO2). No, 'liquid CO2' doesn't count).
  This is a very long time - and the main reason why tanks without CO2 injection are in many ways more difficult for beginners. It is like trying to build muscle with limited protein. Possible, but much harder;
  
  Observe new shoots- if they are healthy and algae free, it is a sign that the plants are progressing on the right path.
  
  As a rule, algae-infested leaves do not become uninfested.
  Deteriorating leaves do not "heal," unlike our skin.
  Instead, plants concentrate on growing new leaves.
  
  For stem plants, we would simply replant the healthy tops and discard the algae-infested lower portions after the healthy tops grow tall.

What about dosing anti-algae products?

If you have a Dutch-style tank, this is generally unnecessary, as fast-growers (with proper tank setup) will almost always outcompete algae after a few weeks. Then it is simply a matter of replanting the healthy tops and discarding the algae-infested older leaves/stems.

However, spot-doing something like APT FIX would be helpful for slow growers such as Bucephalandra, Anubias, Alternanthera reineckii etc. as their old leaves can often recover (one of the secret advantages of slow growers) and new leaves take many days, even weeks, to develop.



Above: It is also fine to spot dose on hardscape/wood to remove algae. We avoid pouring anti-algae agents directly into the tank because they are usually only effective at higher concentrations, and at those levels we risk damaging the fragile and important microbial community that is an important part of achieving tank stability.



Diatoms can arise from planting before the tank was fully cycled.
Although they look nasty, experienced aquarists know that they are actually quite harmless and disappear quickly once the tank has stabilized.
In general, we should not need to use algae treatment products on diatoms.