Can we chant Vishnu Sahastranaam and do nirjala every Ekadashi

Hare Krishna prabhuji 
Dandwat pranam 

 *[Perplexity - what to do, what not to do]* 

In this material nature, due to our imperfections and ignorance, we come across such situations where we are in doubt - what to do, what not to do, how to do, etc.
In Bhagwatgita, Arjun was in the same position when he saw his nears and dears standing I front of him as enemy. He didn’t know what to do. As he was a devotee of Krishna, he approached him in full surrender. -

कार्पण्यदोषोपहतस्वभावः
पृच्छामि त्वां धर्मसम्मूढचेताः ।
यच्छ्रेयः स्यान्निश्‍चितं ब्रूहि तन्मे
शिष्यस्तेऽहं शाधि मां त्वां प्रपन्नम् 
-BG 2.7

Translation
Now I am confused about my duty and have lost all composure because of miserly weakness. In this condition I am asking You to tell me for certain what is best for me. *Now I am Your disciple, and a soul surrendered unto You.* Please instruct me.

Prabhupad says in purport-
By nature’s own way the complete system of material activities is a source of perplexity for everyone. *In every step there is perplexity,* and therefore it behooves one to approach a bona fide spiritual master who can give one proper guidance for executing the purpose of life. All Vedic literatures advise us to approach a bona fide spiritual master to get free from the perplexities of life.

One should have faith in Krishna, and likewise one should have complete faith in the instructions of the spiritual master. Faith is very important to gain Sikruti in life. In bhagwatgita lord explains that when a person has faith on the masters instructions, when they are determined in one goal, he progresses. And when one is diverted in many routes, it is very difficult for him to be stagnant in this world.

व्यवसायात्मिका बुद्धिरेकेह कुरूनन्दन ।
बहुशाखा ह्यनन्ताश्च बुद्धयोऽव्यवसायिनाम् 
-BG 2.41

Translation
Those who are on this path are resolute in purpose, and their aim is one. O beloved child of the Kurus, *the intelligence of those who are irresolute is many-branched.* 

This is very simple theory, if one shall remain focused to the instructions of a bonafide spiritual master, there is no risk of one’s intelligence being irresolute. In this verse, the lord has also explained the root cause of this condition I.e., when a person becomes many-branched. 

In the purport Prabhupada takes example of CC Madhya 22.62 -
śraddhā’-śabde – viśvāsa kahe sudṛḍha niścaya
kṛṣṇe bhakti kaile sarva-karma kṛta haya

Translation—
“Śraddhā is confident, firm faith that by rendering transcendental loving service to Kṛṣṇa one automatically performs all subsidiary activities. Such faith is favorable to the discharge of devotional service.
Prabhupada further says in purport-
Service in Kṛṣṇa consciousness is, however, *best practiced under the able guidance of a spiritual master who is a bona fide representative of Kṛṣṇa* , who knows the nature of the student and who can guide him to act in Kṛṣṇa consciousness.

 *[One Goal - Surrender To Guru and Krishna]* 

In Bhakti marg, one should understand that the sole purpose of any activity we do is to satisfy Guru and Krishna with devotional service. One can achieve this by surrendering himself to Guru/Krishna and rendering most honest devotional service unto them. This is Krishna consciousness. 
One cannot achieve this merely by running behind what’s written is specific portions of Vedas or by following what one hears from others. 

Therefore Narottam Das Thakur has written -
 *Sri Guru Charana Padma, Kevala Bhakti Sadma*
 *Guru mukha Padhna Vakya, Chit te kareya Ekya* 

Here the word “Kevala” means “Only” defines the absolute necessity of being focused in Guru and his instructions. Serving the devine lotus feet’s of our Spiritual master is the *ONLY* Sadhna for a devotee.
Whatever words comes out from the devine mouth of our spiritual master, it makes our Chit in-line with the mood and mission of our Guru.

 *If one is not surrendered himself on its Guru, he will never be able to surrender before Krishna.* 
Krishna when had took avatara in Dwapar yuga also had his spiritual master i.e., Sandeepani Muni. He being the supreme personality of Godhead, through this example has taught us the importance of surrendering to a bonafide spiritual master.

Our only aim should be to render first class devotional service go Guru/Krishna.
Whatever activities we do - chanting, sangkirtan, Fasting on Ekadashi, etc., *are not insignificant* . They are measures  to *supplement our endeavours of being in Krishna consciousness 24 hours a day.* Their goal is to facilitate a bigger cause, and not to give us any immediate frutitive result which we can enjoy. We can’t enjoy anything. We are material beings. Only Krishna is the supreme enjoyer of all the things.
Hence we should remain focused in the instructions of our spiritual masters and follow them diligently. Everything else what we hear in this world is obsolete. 

[The Solution]

One should remain focused on the instructions of a bonafide master and avoid getting into delusions. When he does so, as mentioned in BG 2.52, he becomes indifferent to what been heard. 
Prabhupada writes in it’s purport-
When a person factually understands Kṛṣṇan and his relationship with Kṛṣṇa, *he naturally becomes completely indifferent to the rituals of fruitive activities,* even though an experienced brāhmaṇa.
When a person does so, he gets into the transcendental consciousness as explained by lord in below -
श्रीभगवानुवाच
प्रजहाति यदा कामान्सर्वान्पार्थ मनोगतान् ।
आत्मन्येवात्मना तुष्टः स्थितप्रज्ञस्तदोच्यते ॥
-BG 2.55

Translation
The Supreme Personality of Godhead said: O Pārtha, when a man gives up all varieties of desire for sense gratification, which arise from mental concoction, and when his mind, thus purified, finds satisfaction in the self alone, *then he is said to be in pure transcendental consciousness.* 

This is Krishna consciousness and this is what we need to strive for. Whatever devotional activities we are doing, its ultimate purpose should be to reach this state. Otherwise it is of no use.

Ys, Aditya